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Talk:Van der Waals force

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Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 12:15, 17 January 2022 (UTC)

Misleading description of the repulsive component
At the moment the page says "A repulsive component resulting from the Pauli exclusion principle that prevents the collapse of molecules." This is incorrect, the repulsive component that prevents collapse (into one big united atom) is mainly due to nuclear-nuclear Coulomb repulsion. It's easy to prove that the electronic force on the nuclei in a diatomic is always attractive for all bond lengths. 81.167.188.195 (talk) 19:15, 10 September 2014 (UTC)
 * The nuclear-nuclear Coulomb repulsion in H2 is the same for the spin-singlet as for the spin-triplet state. Yet, at the bonding distance of 1.4 bohr, the triplet state is antibonding (has negative derivative of energy with respect to distance), while the singlet state is bonding (energy has a minimum). The difference is the sign of the energy term that enters through application of the Pauli principle. That is, the repulsion shown by the triplet state is a consequence of the antisymmetrization of the wavefunction. A similar valence-bond type argument can be given for the repulsion of a helium and a hydrogen atom in their ground states. See W. Heitler, Elementary Wave Mechanics, Oxford UP 1956, p. 137.--P.wormer (talk) 08:33, 11 September 2014 (UTC)

Minor work mentioned without citing more important work
In the Definition section of the article, there's some reference to a 2011 work by Zheng and Narayanaswamy. I suspect it was added by one of the two authors and that there are more important historical works. I'm not as well-versed in the this theory and its history, though. Can someone check to see if the cited work is important and whether it should be removed from the Definition section? — Preceding unsigned comment added by Kmdouglass (talk • contribs) 18:36, 15 June 2013 (UTC)
 * The last two paragraphs of the intro are indeed best moved elsewhere.--Ymblanter (talk) 20:44, 15 June 2013 (UTC)

Link with noble gases
I think it is the lack of strong van der waals forces that keep noble gases from condensation. It is true that these forces are present within in all molecules and even in those of the noble gas atoms. However, it is a fact that the bigger the radius of the noble gas atom (more electrons), the higher the boiling point is. This is caused by increased possibilities for temporary dipole formation. So, it strengthens the argument that it is the lack of van der Waals forces that makes the noble gases so stable!

If anyone agrees with me, this has to be corrected.

I agree tho i believe more people should accept before changes are made

chemaddict 10:18, 4 June 2006 (UTC)

Forces
I think that dispersion forces should be under the title of London forces and that Van der Waals force(s) should be a redirect to intermolecular forces. Van der waals forces are called such because they account for the force part of the van der Waals equation (the forces that cause the gas to deviate from ideal behavior). I don't know if the non-London intermolecular forces account for considerable deviation from the ideal when dealing with most gases, but I don't think this is justification for restricting van der Waals to induced dipoles only. The original definition is still the correct one, and to assign both London and van der Waals to dispersion forces is redundant and confusing. Some textbooks get this right and some get it wrong, and that puts everyone on a different page. For what it's worth, the OED makes a point to specify that VdW forces are those caused by dipoles that are "actual or induced". Mauvila 05:21, 9 Dec 2004 (UTC)

I agree. As I understand it, Intermolecular Force = Van der Waals + intermolecular covalent + intermolecular ionic (with the later two being rare) and Van der Waals = London (induced dipole-induced dipole) force + dipole-dipole force + dipole-induced dipole. Therefore there should not be any redirects as Intermolecular includes Van der Waals which includes London forces, but none of them are equivalent. User:TomCounsell

Is anyone familiar with how the forces became known as VdW forces? I am assuming it it because of the VdW equation, that these are the forces responsible for deviation. Is there such thing as VdW volume? (From the other term in the equation.) Anyway, this stuff might be worth mentioning. Mauvila 21:13, 25 May 2006 (UTC)

There's a bit of controversy respect to the proper spelling of the term.See discussion here

According to Dutch spelling rules the correct title is actually Van der Waals force.

According to J.S. Dodd (Ed.), "The ACS Style Guide", ACS, Washington DC, 1986, p.28 the *recommended* spelling is "van der Waals". This style is commonly used in scientific articles.

Survey of 3 physical chemistry Ph.D.s (from different advisors!) agree that permanent dipole-dipole interactions are *not* Van der Waals forces. Van der Waals forces are by definition dynamic. BTW OED should not be an authoritative reference for a chemistry discussion. dllahr 10 Nov 2009 —Preceding undated comment added 15:47, 10 November 2009 (UTC).

Please update that survey to 5!!! It's not acceptable that dipole-dipole interactions are currently included. There is a whole bulk of scientific literature that specifically excludes ANY type of static electrostatic interaction (including dipole-dipole) forces from the term "Van der Waals" interaction.

I would summarize the current use of the term "dispersion force" and "vdW force" as follows. In the physics community, it is custom to use "vdW force" for the force arising from the dynamical correlation in electronic motions in distinct atoms, molecules, or surfaces. In atoms, this may be described best as correlation between dipole fluctuations (oscillations), which is what London derived. Going to molecules, one can thing of the mechanism either in terms of fluctuating dipoles on the whole molecules, or of small fluctuating dipoles on each individual atom of the molecule, or even in terms of charge fluctuations within the molecule, it's all just matter of perspective and mathematical formalism. Going to surfaces, especially metallic, it's best to think about these fluctuations as charge fluctuations (currents). (With two metallic plates at macroscopic distance apart, this is known as the Casimir effect, which is really just a special case of the vdW force.) In this view London dispersion (as published by London) is a certain limited theory (model) of the vdW force that works very well for atoms and small molecules. Physicists would usually not think of permanent (Debye) or induced (Keesom) electrostatic force as part of the vdW force. In chemistry, it has been common to refer to the totality of permanent and induced electrostatic, and dispersion force as vdW forces, because they all contribute to certain degree to the constant $$b$$ in the vdW equation of state. That is, the same thing is "vdW force" for most physicists and "dispersion force" for most chemists. More recently (last two decades), chemists started to use the term "noncovalent interactions" to mean pretty much the same thing as "vdW forces" (in the chemical sense). I would say that chemists today use mostly "noncovalent interactions" and "dispersion force" and "vdW forces" came out of favour. So, this is the current situation. I'm not sure what wikipedia should do in such cases, or whether there is some general policy how to deal with confusing nomenclature. My personal view is that the article on London dispersion and vdW force should be merged (dispersion should redirect to vdW force), the naming situation should be explained in the intro, and the totality of electrostatic and dispersion interactions should be discussed in the article on noncovalent interactions (as it currently is). I would be very happy to make these changes if there is a consensus that this is a good approach. —Jan H. (talk) 09:57, 23 October 2017 (UTC)

Slight mixup in references
There seems to be slight mistake in the reference concerning the relationship between the Casimir force, the Van der Waals force, and Sonoluminesence.

 * Iver Brevik, V. N. Marachevsky, Kimball A. Milton, Identity of the Van der Waals Force and the Casimir Effect and the Irrelevance of these Phenomena to Sonoluminescence,

discussing the relationship between the the three phenomena is not found at hep-th/9901011 but at hep-th/9810062.

The first link points to

 * Kimball A. Milton "The Casimir Effect: Physical Manifestations of Zero Point Energy"

which has a section that discusses the relationship between the Casimir and the Van der Waals force.

cheers

tarek yousef

Achtung!
This page is duplicated(Van der Waals forces & Van der Waals force). One should be purged

London forces named for Fritz London?
Are the London forces named for Fritz London alone, or are they also named for his brother (Heinz London) who worked with him on their superconductivity theories? 194.200.237.219 13:45, 31 January 2006 (UTC)
 * Looking elsewhere, it seems that Fritz London worked on intermolecular forces and published something in 1930 on London dispersion forces. The London brothers work on superconductivity was later, in 1935. 194.200.237.219 15:58, 31 January 2006 (UTC)
 * the paper that made Dispersion popular dates from 1937 and was written by Fritz London while in exile in France. The original work dates from 1930. 92.184.124.117 (talk) 11:28, 14 April 2023 (UTC)

Merger
Van der Waals bonding and Van der Waals force are basically two versions of the same article about the same phenomenon. It is unclear how they got written in parallel, but Van der Waals force seems to be both the more common name for the phenomenon and the more comprehensive (as well as referenced/sourced) article. I propose that Van der Waals bonding be merged into Van der Waals force and made a redirect. MCB 18:00, 24 May 2006 (UTC)
 * Yes i agree, and most english exam bored recognise them more commonly as the Van der Waals forces so i think it is more apt to merge the two articles under one heading - Van der Waals forces. chemaddict 10:18, 4 June 2006 (UTC)
 * I also agree with merger of both pages in question under one, which would be called either "Van der Waals force" or even more generally "Van der Waals interactions". The attractive force between atoms and "bonding" is virtually the same thing. For any person with interest for Van der Waals interactions, it would be more convenient to have facts from both pages combined in one comprehensive page.
 * Agree - wikipedia never lets two articles on the same topic with two different titles co-exist. Merge - mastodon 18:05, 9 June 2006 (UTC)
 * Agree - pointless duplication. PS - If anyone disagrees, perhaps they'd like to write an articale entitled Differences between Van der Waals force and Van der Waals bonding. --Oscar Bravo 06:57, 6 July 2006 (UTC)
 * Poorly excuted merge! I have reverted, all the editor did was delete the content of Van der Waals bonding and redirect! that is not how we do it - Jack (talk) 00:58, 21 July 2006 (UTC)
 * The guideline on merger says, "Cut/paste the non-redundant content from the source page into the destination page." However, after examining both pages, it was quite apparent that there is nothing of value in the "bonding" article that is not already covered here. If you think you can do a better job of merger, by all means feel free. But having the two redundant articles out there is not helpful to Wikipedia. --MCB 04:59, 21 July 2006 (UTC)
 * I fully agree. The text of the bonding article covered ground that is already discussed in this article, as such there is no need to make any changes. I've re-merged the article. Jrockley, if you believe there to be information missing after the merge, please add it to the current article. PureFire 09:43, 27 July 2006 (UTC)

Possessive apostrophe
As far as I know "van der Waals force" is more common than "van der Waals' force". I propose that the article text and title reflect this. — DIV (128.250.204.118 03:39, 6 March 2007 (UTC))

I see this was moved by Thomaslau on 22 November 2006 with the note, "moved Van der Waals force to Van der Waals' forces: The Correct Name". And somehow this was classed as a "minor" edit. It doesn't seem to be a minor edit, and I see no discussion. I'm quite happy with the change to plural, but not the apostrophe. — DIV (128.250.204.118 04:23, 6 March 2007 (UTC))

 * fully agree, van der waals had no idea of what force was responsible for condensed phase. This dichotomy came way after his demise, during the 1920s' there were hot discussions about intermolecular forces, the advent of quantum physics led the way to London's first description of the so called Dispersion force. Therefore I would add a more historical paragraph that can be documented easily by checking Rowlinson's book on the history of Cohesion. 92.184.124.117 (talk) 11:36, 14 April 2023 (UTC)

"Van der Waals" is singular, so to make it possessive you would typically do "Van der Waals's", even though it already ends in "s". Since no one says "Van der Waals's force", "Van der Waals force" is correct, with "Van der Waals" being a description of the type of force, not a possessive. --129.2.170.33 00:42, 14 March 2007 (UTC)

 * I've moved the article back. --Itub 20:57, 3 April 2007 (UTC)

London force only a sub part of VDW

 * "Van der Waals bonding, also known as London force, instantaneous dipole effect, and induced dipole interaction"

This is not an entirely true statement as the London interaction is only one of three (arguably there are more) intermolecular interactions in Van der Waals bonding. It is agreed in most systems that the London interactions is the only interaction to consider as the other two, Debye and Keesom, interactions sum to zero, however to totally ignore these or reference these interactions would be undermining the state of present surface and materials science.

Therefore for "Van der Waals bonding" to be a complete page I would have agree for the merger of this article and Van der Waals force, as these contributions are sighted.

Dr dagger 03:32, 13 June 2006 (UTC)

 * Right. Bot no one described vdW interactions as a combination of Debye (dipole-dipole), Keesome (dipole-induced dipole), and London (dispersion attraction) forces in the article. Biophys 04:35, 18 October 2007 (UTC) BTW, that is why they are "forces" (plural), not a force.Biophys 04:52, 18 October 2007 (UTC)

Shouldn't "oval" be "ellipsoid"?
The article says that the surrounding cloud forms, not a (3-dimensional) sphere, but rather a (2-dimensional) oval. I think "ellipsoid" is correct. --Carl Manaster

Yes - I fixed it. PAR 01:28, 12 October 2006 (UTC)

Dipole moment of ellipsoid
The article says: "However, the larger the atom of the noble gas, the easier it is to condense the gas. This is because a larger atom has a larger electron cloud, which more readily forms an ellipsoid, making the atom a temporary dipole."

I find this possibly confusing. The dipole moment of an ellipsoidal "electron cloud" with respect to its center is zero. I understand what is the intended meaning of the sentence I quoted, but I think it needs to be rewritten.
 * Presumably "center" needs to be replaced by "focus", or whatever focus generalizes to in the case of more than one electron. Vaughan Pratt (talk) 21:49, 3 December 2020 (UTC)

Hamaker Force Interactions
An moved the information from article Hamaker Force Interactions and redirected the article to Can der Waals force. I think the information below is rubbish - as googling the term find nothing except Hamaker constant, and I did not think Van der Waal's could be between two macroscopic bodies. So anyway - I have put the information below and if needed someone can put it into this article.

Hamaker Force Interactions are the Van Der Waal's forces between two macroscopic bodies. Hamaker first performed the integration of the interaction potential in 1937 using the following assumptions:

1) the total interaction can be solved by summing the pairs of force interactions.

2) the summation of assumption 1) can be approximated by integrating over the volume of the macroscopic body assuming that the volume of each atom is $$dV$$ with density $$p$$

3) the material properties $$p$$ and $$C6$$ (interaction constant from Van Der Waal's equation)

Cheers --Lethaniol 14:44, 25 October 2006 (UTC)

 * There is an orphaned article at Hamaker theory. Can someone work on this?  — DIV (128.250.204.118 01:44, 23 May 2007 (UTC))

 * Good point. Actually important subject is Hamaker constant that has been measured for interactions between different materials in different media. We must have article about it.Biophys 04:41, 18 October 2007 (UTC)

Van der Waals forces and Intermolecular force
Van der Waals forces are also discussed in detail in Intermolecular force. Is there any reason why this article can not be merged into Intermolecular force. It certailny looks a mess from the point of view of doing main article links from Chemical bond. What is the view or should I add merge tags now? --Bduke 21:59, 28 November 2006 (UTC)
 * There definitely needs to be a bit more cohesiveness between the two articles, or at least a reference... but there's enough to say to merit separate articles. ··gracefool☺ 12:47, 6 September 2010 (UTC)
 * Another point to consider: The lead para in Van_der_Waals_force begins "Van der Waals forces include attractions between atoms, molecules, and surfaces." which frames it in terms beyond "intermolecular forces". The remaining paragraphs of this section discuss only the narrow framing. How should this be addressed for clarity and consistency? —(talk • contribs) 18:59, 11 September 2010 (UTC) --humanengr (talk) 21:42, 11 September 2010 (UTC)

Adhesives
Can regular glue or tape stick to atomically smooth surfaces (or even just surfaces with no atomic overhangs)? If so, is it due to Van der Waals' forces? —Ben FrantzDale 17:02, 17 January 2007 (UTC)

 * See the reference about the geckos for a discussion of adhesion to smooth surfaces attributed to VdW forces. Itub 18:29, 17 January 2007 (UTC)
 * I saw a talk on that this morning, that's what brought me here. I am particularly curious about conventional adhesives, though, such as superglue. I think I found an answer on StraitDope.com which basically says "it could be Van der Waals' forces but the jury is still out. (It seems surprising that we would know more about gecko adhesion than about simple superglue. Science must know the answer to "does glue stick to an atomically-smooth surface".) —Ben FrantzDale 18:59, 17 January 2007 (UTC)

Van der walls forces in rubber
I have just read an article in a motor cycle magazine, discussing the properties of tyres, where they claim that the rubber tyres provide traction by two methods, firstly by mechanical traction which I have no problem with, and secondly by Van der Waals forces. Do Van der Waals forces play a major part in the traction provided by rubber tyres?? Any comments appreciated, Thanks
 * Sounds like a load of… don’t think that’s correct, friction would be a good article to read up on the topic though. --Van helsing 21:33, 25 June 2007 (UTC)

Yes, but isn't friction caused by Van der Waals forces and other weak intermolecular interactions? Otherwise what is causing friction? — Preceding unsigned comment added by 67.193.134.223 (talk) 00:54, 24 January 2012 (UTC)

Nomenclature
The terminology is perfectly correct to what is common in colloid science or material science. But if other fields follow different terminology, that happens, and it would be helpful if you could formulate an appropriate sentence in the article. Bubblerock2 (talk) 10:40, 10 August 2013 (UTC)

Hello. I believe quite strongly that the terminology being used on this page is specifically skewed to one branch of science. Although physicists may use this terminology, biochemists make different distinctions. The term, van der Waals force is used synonymously with London dispersion forces and the others that are grouped here in this article as van der Waals forces, are instead called each by their individual name to distinguish them from one another. You should read Science and Nature articles on protein structure and see what they refer to as van der Waals forces. Pick any one. There are a plethora. There is your source. Or go to the pdb, and choose just about any article. 70.194.6.42 (talk) 18:21, 1 August 2013 (UTC) _______ Somebody said that London forces are incorrectly referred to as Van der Waals forces. This is an example of an interesting point that touches on more Wikipedia articles. Who or what determines what nomenclature is correct? Personally I would take the stance of modern dictionary writers: describe what you observe, not what you think should be observed. If one finds "Van der Waals force" in the literature as synonym for "London force", then who is to say that it is incorrect? Maybe after some IUPAC or SI committee has made a decision? But then we should definitely refer to this decision in our disapproval.--P.wormer 07:57, 6 July 2007 (UTC)

 * The solution is simple: such statements should be attributed to a source or removed. So I agree that removing it was correct. If I may venture a guess, I would say that equating London forces with Van der Waals forces could be seen as incorrect in the sense that one could consider VdW forces to include a repulsion term, while London forces refer only to the attractive interaction. --Itub 08:16, 10 July 2007 (UTC)

 * The truth here is that it is dependant on the prevailing semantics. In Biochemistry we frequently refer to Van der Waal force as being synonymous with london forces... and my old Oxtoby text still states this.  Most modern texts say it includes all the imf's.  I think you'll find it to represent London forces more in biological texts than in Chemistry texts - and you have to be aware of the possible multiple definitions and meanings of this term.  There is also a dipole/h-bond cancellation effect going on in macromolecules that leads people to only care about buried surface areas and vdw surface sizes, and ignore the other imf's... which is why the entire definition is loose and weak at best.  —Preceding unsigned comment added by 168.156.37.112 (talk) 21:01, 21 May 2010 (UTC)

 * To add to my last point about semantics. The Biochemistry text "Stryer," which is widely used, essentially defines VdW as London forces (although it extends the description to allow for repulsion).  So if someone wants to reintroduce this ambiguity in the definition, that is your source.  —Preceding unsigned comment added by 168.156.37.112 (talk) 21:13, 21 May 2010 (UTC)

van der Waals forces are attractive. This article gives the impression that there are repulsive van der Waals forces. I'm guessing this mistake comes from the van der Waals and overlap (repulsive) forces often being grouped into the same term in the calculation of nonbonded interactions, but it is still a mistake. — Preceding unsigned comment added by 152.7.224.3 (talk) 20:41, 11 May 2015 (UTC)

Fraught with Errors
The VDW page is fraufht with minor errors that add up to a misleading article. —Preceding unsigned comment added by 151.199.239.37 (talk • contribs)
 * It would be helpful if you could address which concerns you have in particular, thanks. --Van helsing 17:54, 7 July 2007 (UTC)

I just mentioned this above, but to begin with, there is no such thing as repulsive van der Waals forces (I'm not the OP) — Preceding unsigned comment added by 152.7.224.3 (talk) 20:41, 11 May 2015 (UTC)
 * Can you cite your source for this statement? Are London forces not repulsive? I am genuinely asking because I came to this article for clarification on this point and found I had to search elsewhere for clarification. Unless "dispersion" is not considered "repulsive" I have to disagree with your statement. — Preceding unsigned comment added by Rdelwiche (talk • contribs) 04:52, 16 April 2018 (UTC)

Needs an intro section
This article is impenetrable and needs an intro section such as this Frostburg article I found. —Preceding unsigned comment added by Feldon23 (talk • contribs)

 * I did a rewrite, put a link to the Frostburg article, and wrote an e-mail to its author (asking him to remove a sentence in which he suggests that the Van der Waals force is short-ranged).--P.wormer 12:56, 31 July 2007 (UTC)

London forces weaker than permanent dipole-dipole interactions?
“London forces are also present in polar molecules, but they are usually only a small part of the total interaction force....In vacuum, London forces are weaker than other intermolecular forces such as ionic interactions, hydrogen bonding, or permanent dipole-dipole interactions.”

I suggest that the article should mention that different sources give opposite answers to the question of the relative strength of London forces in polar molecules.

Linus Pauling, Van der Waals Forces. Melting Points and Boililng Points, pg 394, General Chemistry, Dover, 1970 "The theory of van der Waals force of attraction between molecules was developed by the physicist F. London in 1929. It had been suggested that the van der Waals attraction between two HCL molecules (or other molecules with a permanent dipole moment; Section 6.8) was the result of the interaction of the permanent dipole moments.  Careful calculations of this energy of attraction for two HCl molecules, however, gave a result only 10% of the observed interaction energy.  Moreover the interaction energy of molecules of xenon (boiling point -107 degrees C) is nearly as great as that of molecules of hydrogen chloride (boiling point -84 degrees C), although the molecules of xenon, which are single atoms, have no permanent electric dipole moment."

"van der Waals forces." Encyclopædia Britannica. 2007. Encyclopædia Britannica Online. 25 Nov. 2007 . “These specific interactions, or forces, arising from electron fluctuations in molecules (known as London forces, or dispersion forces) are present even between permanently polar molecules and produce, generally, the largest of the three contributions to intermolecular forces.”

Intermolecular Bonding - Van Der Waals Forces, ChemGuide, Jim Clark http://www.chemguide.co.uk/atoms/bonding/vdw.html “Surprisingly dipole-dipole attractions are fairly minor compared with dispersion forces, and their effect can only really be seen if you compare two molecules with the same number of electrons and the same size. [He then gives examples.]

However, other reputable sources give the same answer currenty used in this article (which is the answer I remembered from the chemistry class I took back in 1968):

Paul Foglino, London Dispersion Forces, pg 47, Cracking the AP Chemistry Exam, 2006-2007 Edition, The Princeton Review, Random House. “London dispersion forces are even weaker than dipole-dipole forces”

Joseph A. Mascetta, London Forces, pg 52, Chemistry the Easy Way, Third Edition, Barron’s, 1996 “London forces are about one tenth the force of most dipole interactions and are the weakest of all the electrical forces that act between atoms or molecules” [This might be an accidental inversion of Pauling’s summary of London that permanent dipole interactions were “only 10% of the observed interaction energy”]

''When reputable sources disagree, an encyclopedia should not attempt to choose the best answer. Instead it should inform the readers of the disagreement.'' Ray Eston Smith Jr (talk) 20:15, 25 November 2007 (UTC)

Surely the point here is that London Forces depend on the size of the molecule. The force between two polymer chains in parallel is very large indeed. --Bduke (talk) 21:38, 25 November 2007 (UTC)

HCl is one of the smallest polar molecules. But even in HCL, the permanent dipole accounts for only 10% of the total van der Waals force. My point is that a lot of sources are providing wrong information about the relative strength of London forces vs permanent-dipole forces. I think even if this article gave the correct information, it would still be misleading if it didn't point that many sources disagree. Ray Eston Smith Jr (talk) 18:53, 26 November 2007 (UTC)

Make up your mind about capitalization of Van when it appears in the middle of the sentence.
Although I am Dutch and know the rules, I am not going to be precious about it, and just ask the head author to adopt the same convention throughout. —Preceding unsigned comment added by 137.205.183.4 (talk) 09:32, 21 February 2008 (UTC)

 * Done. But remember that there's no "head author"--anyone can fix errors, including you! --Itub (talk) 10:07, 21 February 2008 (UTC)

Lowercase title
This article had the 'lowercase' template so that the title would display with an initial lowercase letter (i.e. 'van der Waals force'). I've edited the page to remove the template, because although the 'van' in 'van der Waals' is written lowercase, the 'v' would still be written uppercase at the beginning of a sentence. I therefore think it's appropriate to have the 'v' capitalised in the title (van der Waals equation already had an uppercase 'v' anyway). If I'm wrong though, feel free to stick it back in. TheLewisRepublic (talk) 15:11, 21 September 2009 (UTC)

Van should be capitalized unless preceded by first name
I should note that the standard way of writing Dutch names entails that the first "tussenvoegsel" (in this case, "van") should only be lowercase if the subject's first name precedes it. So, Johannes Diderik van der Waals is correct, but van der Waals is not. In the latter case, it should be Van der Waals (yes, mid-sentence too). 195.241.69.171 (talk) 22:46, 28 November 2009 (UTC)
 * I've edited the article. 195.241.69.171 (talk) 22:49, 28 November 2009 (UTC)

 * "van der Waals" in the context of the article is not used as a person's name, but as the name of a physical phenomenon. I am doubtful whether a capitalized "Van" is in common use at all, although such use may be increasing. Here are some non-scientific search results, first limited to physics and chemistry subject areas:
 * Scholar search between 1900 and 1990 gives only "van der Waals"
 * Scholar search between 1990 and 2009 gives one "Van der Waals" and nine "van der Waals"
 * Scholar search between 2001 and 2009 gives only "van der Waals" in the first ten results
 * Extending the search to all subject areas gave almost the same results (2 "Van" versus 8 "van" for 1990 to 2009). There may very well be a growing use of "Van der Waals", but finding evidence is not easy. A web search for "Van der waals" BBC did find a few more: out of ten results, had "or Van der Waals forces";  had "called 'Van der Waals' forces"; facebook page  had "The Van Der Waals event"; but generally the majority used lowercase. I also looked at CNN, Herald and Tribune and the New York Times: all except the last exclusively used lower case, the New York Times had one example of upper case and three examples of lower case in the first 20 results.
 * In light of the above I have returned the article to use what appears to be the common usage. However it could still be interesting to mention whether a change in spelling to "Van der Waals" is ocurring in common use, or in particular fields. -84user (talk) 15:02, 29 November 2009 (UTC)
 * Are we after "correct" or "accepted" usage here?
 * If it's not a person's name, why even capitalize "Waals"? This seems inconsistent.  Why do we capitalize "London" forces?  If it's not because it's a person's name then it must be for being the name of a phenomenon - just the same as the more general Van der Waals forces.  On the other hand, all the German literature of the time referred to "van der Waalsschen Kräfte" or "van der Waalsschen Kohäsionskräfte," so "van der Waals" seems to have been the accepted form at least then, but that might have been simply in keeping with the usage of the German "von", which is never capitalized. 69.92.2.30 (talk) 15:52, 4 April 2022 (UTC)
 * Agreed, it seems a bit off with the lower case "v". Anything else derived from a normally capitalised name, like Bose–Einstein condensate, is capitalised. ghouston (talk) 12:11, 18 May 2024 (UTC)
 * Compare with the Johannes Diderik van der Waals article, "Van der Waals" is used there when appropriate. ghouston (talk) 12:15, 18 May 2024 (UTC)
 * Also, with Van de Graaff generator. ghouston (talk) 00:18, 19 May 2024 (UTC)

Worth mentioning?
Small Asteroids Are Held Together by Van Der Waals Forces http://technologyreview.com/blog/arxiv/24818/ Sbowers3 (talk) 00:46, 18 February 2010 (UTC)

equation
The section "calculation" is pretty bare -- just the equation. Shouldn't it at least state that usually s=12 and t=6 for the exponents? A sketch of the potential would be nice. There could be a discussion of the existence of a minimum, vibrations around the minimum, relating the binding energy to the two constant, etc.--75.83.69.196 (talk) 17:06, 27 February 2010 (UTC)

Dipole-dipole force
An editor removed the dipole-dipole force a couple of months ago, so that we now have a list of "four" intermolecular forces that only includes three. I'm restoring this force, as per the IUPAC Gold Book and also this reference. If there is an authoritative source that clearly excludes dipole-dipole interactions, please cite it here – then we could say that there is disagreement among chemists. Until then, dipole-dipole should stay. Lfh (talk) 16:01, 24 April 2011 (UTC)

Gecko research
New evidence suggests that the effect seen in the Huber et al. (2005) paper is an artifact of dehydration. I have edited that section accordingly. —Preceding unsigned comment added by Apeattie (talk • contribs) 05:09, 23 May 2011 (UTC)

why is water polar than hydrogenfloride but water exist as liquid and has a boiling point of 100 degrees celcius — Preceding unsigned comment added by 41.210.29.244 (talk) 17:41, 29 June 2011 (UTC)

While these Geckos are fun, this topic is being overdone a bit. Finally, its a page on Van der Waals forces and not about Geckos. Bubblerock2 (talk) 15:03, 7 June 2014 (UTC)

Geckos' Mastery of Physical Theory.
We are told that "Geckos can stick to walls and ceilings because of theory of forces; see the section below." I already knew that geckos were masters of life insurance, but their knowledge of physics came as a surprise to me. 207.245.236.154 (talk) 09:29, 29 October 2013 (UTC)

uncited plagiarism
http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Van_der_Waals_force.html

Corresponds to the preamble of the article. StainlessSteelScorpion (talk) 00:53, 13 November 2013 (UTC)

 * If you look at the bottom above page, you will see that it is the other way around. The Princeton article is taken from Wikipedia. PAR (talk) 03:19, 13 November 2013 (UTC)

Instantaneous dipoles?
The article on London dispersion force says ''Note that this final London equation does not contain instantaneous dipoles (see molecular dipoles). The "explanation" of the dispersion force as the interaction between two such dipoles was invented after London arrived at the proper quantum mechanical theory.'' I think that's right and this article is wrong in saying that the London dispersion force is based on instantaneous dipoles, but I don't have the expertise to write a summary with any confidence of getting it right. --Dan Wylie-Sears 2 (talk) 01:07, 28 May 2014 (UTC)

Examples
The article starts by explaining the forces are not chemical bond forces. Ok. So what *are* they? And we leap into quantum mechanics. Now, I happen to know a bit about QM, but I have met people, who, sadly, know nothing about it. I'm afraid this article fails completely to enlighten them as to what van der Waals forces might be, and what role they play in nature.

The first examples I see of the forces are in their utilization by Gekos. Really??? So, is that how the forces were discovered? Gekos?

Could it be that the forces play a role in some familiar materials? Maybe water? I don't see water mentioned on the page... Does that mean van der Waals means Gekos? Stevan White (talk) 16:56, 20 July 2017 (UTC)

 * Yes, I agree, and think that the role of van der Waals force in water (cohesion and adhesion) could be cited as examples, as well as some of its roles in biology, such as protein folding. Since all of these are attraction between dipoles, an example of non-polar dipersion, such as properties of halogens due to London dispersion force should also be included. Links to the articles on these topics could also be added to the "See also" section. — Preceding unsigned comment added by Rdelwiche (talk • contribs) 05:02, 16 April 2018 (UTC)
 * Cohesion (chemistry)
 * Adhesion
 * Protein Folding
 * London Dispersion Force

Proposals for some improvements
Within inverted commas, here is a sentence in the last part of the introduction of the article: "If no other forces are present, the point at which the force becomes repulsive rather than attractive as two atoms near one another is called the van der Waals contact distance". In my opinion, it should be preceded by another sentence specifying that the forces we are dealing with can be attractive or repulsive. In addition, the same sentence should be modified as follows: "If no other forces are present, the point at which the force becomes repulsive rather than attractive as two atoms approach one another is called the van der Waals contact distance". Shortly after, another passage says: "The resulting van der Waals forces can be attractive or repulsive.[3] It is also sometimes used loosely as a synonym for the totality of intermolecular forces.[4]" In my opinion, the passage should be rewritten as follows: "The resulting van der Waals forces can be attractive or repulsive.[3] Term "Van der Waals forces" is also sometimes used loosely as a synonym for the totality of intermolecular forces.[4]"Ekisbares (talk) 08:19, 25 October 2017 (UTC)

 * I agree in general. As I wrote above in section Forces, I think that the introduction should clearly distinguish two use cases of the term. One is for the exclusively attractive force originating from charge (dipole) fluctuations and their interaction. This is what the article should be about. The other is a synonym for Non-covalent interactions, to which this article should link. It should also make clear that the equilibrium structure of vdW-bound systems is a result of the vdW attraction and Pauli repulsion, but that the latter is not considered a part of the vdW force. Finally, it should make clear that all these distinctions are somewhat theoretical, and that while they are clear in the extremes (long distances between molecules, rare-gas dimers, two metallic plates), in most cases they depend on a particular framework within which one formulates the different contributions. —Jan H. (talk) 09:30, 25 October 2017 (UTC)

I have to beg the pardon of the readers as regards the proposed replacement of "near" with "approach". I did not know the existence of verb "to near". So the proposed replacement is to be considered as no more valid. On the contrary, the proposal of replacing "It" with "Term "Van der Waals forces"" remains valid.Ekisbares (talk) 06:55, 29 October 2017 (UTC)

In the absence of comments, I replaced "It" with "Term "Van der Waals forces"" as proposed.Ekisbares (talk) 21:24, 11 February 2018 (UTC)

The first force
A repulsive component resulting from the Pauli exclusion principle that prevents the collapse of molecules. Is this an intermolecular force? Weiwei961208 (talk) 20:42, 3 October 2018 (UTC)

 * sure it is 92.184.124.117 (talk) 11:24, 14 April 2023 (UTC)

Spider-Man Reference
Last sentence - The troops gaining “Spider-Man like abilities” is just silly, especially for a physics article. The analogy isn’t even correct either. — Preceding unsigned comment added by 103.106.91.140 (talk) 14:32, 7 November 2020 (UTC)

No formulas for repulsion?
I came to this article hoping to learn how to calculate contact distance But although the article talks in general terms about both attractive and repulsive intermolecular forces, its extensive quantitative component focuses on attractive van der Waals forces to the complete exclusion of repulsive ones, leaving me no better informed than before as to how to compute contact distance.

Would it be possible for someone familiar with this material to add a formula or two for repulsive van der Waals forces? Vaughan Pratt (talk) 00:27, 4 December 2020 (UTC)
 * They probably could be included, but this is something debatable. The the "vdW forces" are usually described as representing only the attractive part of the Lennard-Jones potential, but the repulsive part has a very different physical origin than the attractive vdW forces. My very best wishes (talk) 18:11, 18 December 2020 (UTC)
 * Thanks very much for drawing my attention to the Lennard-Jones potential, which turns out to contain the formula I needed. What threw me off was the many mentions of repulsion in the first half combined with no mention at all of Lennard-Jones in the quantitative section.  It took me a while, including a careful read of Hamaker's 1937 paper, before I finally realized that all three terms in Hamaker's complicated formula were for attraction only.
 * I'd always thought of attractive and repulsive intermolecular forces as equally important, but it looks like Wikipedia for some reason emphasizes the attractive forces. The article Intermolecular force has the same emphasis.
 * Now that I've looked further, I see that another name for the Lennard-Jones potential is the 12-6 potential, where the two numbers are the exponents of distance for respectively the repulsive and attractive forces. A more general potential is the m-6-8 potential where m is a variable that replaces 12 and can be set anywhere between 8 and 18 while 8 is a second attractive term supplementing 6.  It looks like Wikipedia has nothing about it.   Vaughan Pratt (talk) 22:50, 21 December 2020 (UTC)

Superfluidity
Anyone can reliably (based on sources) tell if this force is somehow linked to superfluidity? AXO NOV (talk) ⚑ 09:13, 22 August 2021 (UTC)

Cancelling out Van Der Walls forces
There is a material called hexamethyldisilazane which can make silicon surfaces hydrophobic. Given that the water is influenced by this ion bonding chemistry, I think it's rational to tie the VW force to the ionic-electronic one. Do we have any sources on that? AXO NOV (talk) ⚑ 16:24, 20 June 2022 (UTC)

Rewrite
The article as it stands now is almost completely wrong. Someone must be protecting poorly written work here. Vdw forces are defined based on a one sixth power cutoff and none of this mumbo jumbo. Standard conditions is not a temperature defined value. Virtually every sentence in the definition part is wrong. Someone nuke it and start over with an Atkins Jones definition. 73.109.135.112 (talk) 01:25, 27 January 2023 (UTC)

title: Talk:Van der Waals force


text:
Wikipedia:Articles for deletion/Gogo (Final Fantasy VI)

Gogo (Final Fantasy VI)
Intermittently intelligible fancruft about one character in part six of the "Final Fantasy" series. Gogo already has his/her moment of W'pedia fame within Final Fantasy VI; this page suggests that even for the most fanatic, there's not much more to say. On the other hand if it's Official Wikipedia Policy to devote an article to every character within every episode of this apparently interminable saga of commerce popular culture, I may have to retract my suggestion. (Yet if this isn't fancruft, what is?) -- Hoary 05:23, 9 Dec 2004 (UTC)
 * FECES, Foghat, or GOOPTI, whatever you want to chalk it up as, it's fancruft. Delete. -R. fiend 06:05, 9 Dec 2004 (UTC)
 * Merge and Redirect to List of characters from Final Fantasy VI (or something) along with the rest of the cast. And remove those move lists from all of those articles and transwiki them to the guide at Wikibooks. -- [[User:Bobdoe|Bobdoe (Talk)]] 06:23, 9 Dec 2004 (UTC)
 * Delete. An unknown man or woman found within a monster oon triangle island.  Says it all, really.  The bulk of the article seems to be instructions aimed at enabling somebody to cheat at the game, which it seems to me rather defeats the point of playing a game in the first place. "Goalkeeper.  A player who stands in the goalmouth.  You can win the game by waiting until the referee isn't looking and then giving him a sharp punch to the stomach" --[[User:Tony Sidaway|Tony Sidaway|Talk]] 06:35, 9 Dec 2004 (UTC)
 * It's not cheating, it's an easter egg. The game company deliberately programmed this character in so that if you went through this special sequence of actions, you could get this surprising bonus to your play.  Calling it "cheating" because it's counter-intuitive and not everybody knows you can do it is like calling "en passant" cheating for the same reasons. -- Antaeus Feldspar 19:37, 9 Dec 2004 (UTC)
 * En passant is a poor choice; it's a documented rule of the game and no list of the rules is complete without it. Whatever you call it, this feature has the appearance of a cheat.  I would not want to devote a whole entry to each such cheat or easter egg, but it might be reasonable to write an article about them with Gogo as an illustration.  --[[User:Tony Sidaway|Tony Sidaway|Talk]] 20:22, 9 Dec 2004 (UTC)
 * It can't be a perfect analogy because the "rules" of a video game are whatever the makers programmed them to be. The makers deliberately programmed this video game so that you could add this mysterious person to your party, and they had to do quite a bit of work to do so, just as much work as for any of the other characters; it's not as if this was some sort of bug in the program and the article was about how to exploit the bug.  The "appearance of a cheat" is entirely, I'm afraid, in your own perception. -- Antaeus Feldspar 21:45, 9 Dec 2004 (UTC)
 * Delete. Aren't there enough websites entirely devoted to bit-part characters and minutae involving Star Trek, Star Wars, Final Fantasy...Rje 06:38, 9 Dec 2004 (UTC)
 * Delete. I'm not necessarily opposed to "fancruft", but there has to be more than this to merit a separate article. Final Fantasy VI already mentions him or her; any additional information can be added there. [[User:Knowledge Seeker|Knowledge Seeker দ (talk)]] 08:54, 9 Dec 2004 (UTC) I change my vote to redirect to Final Fantasy VI. — [[User:Knowledge Seeker|Knowledge Seeker দ (talk)]] 09:00, 9 Dec 2004 (UTC)
 * Keep. There used to be alot of talk about Gogo while ago, however it needs to be expanded severely, and there's alot more information available, like the various theories that he is Golblez from FFIV. -- [User:Omniscientist|Omniscientist]] 3:00, 9 Dec 2004 (UTC)

 * Delete: Utterly insignificant trivia.  This is fan stuff that isn't necessary or desirable in a general encyclopedia.  Gogo-Nono.  (A friend told me, about pursuing a young lady already in a romantic relationship, "Just because there's a goalie, that doesn't mean you can't score.")  Geogre 14:51, 9 Dec 2004 (UTC)
 * Delete. Fancruft. Do people just not understand what an encyclopaedia is? Delete this and all of the rest of the trivial crufty fan-based banality. --Bucephalus 15:33, 9 Dec 2004 (UTC)

 * Delete. No redirect necessary under such a title.  [[User:GRider|GRider\talk]] 17:19, 9 Dec 2004 (UTC)
 * Delete without redirect. I've merged what I thought was relevant content into Final Fantasy VI. -- Antaeus Feldspar 19:37, 9 Dec 2004 (UTC)
 * Delete. Especially now there's nothing left... P Ingerson 00:29, 10 Dec 2004 (UTC)
 * Bad article—reasonable subject, though. Keep. Very notable game, one of the most important SNES RPGs, deserves to be covered in considerable detail. Everyking 06:36, 10 Dec 2004 (UTC)
 * Agreed. Terrific character, great series of games.  However, I seem to remember Gogo from FFIII and FFIV as well.  Any info that can be added to this would be utterly lost in the title.  I stumbled on an article about another FF character, Terra Branford just the other day.  Pretty good one, too.  No vote, but leaning toward keep and expand. - Lucky 6.9 02:05, 11 Dec 2004 (UTC)
 * Merge and redirect. I wish that the people editing these articles would stick the characters in one article per game, rather than creating a stubby, context-vacated, nearly useless article for each character.  -Sean Curtin 05:38, Dec 11, 2004 (UTC)
 * Seems like whatever relevant info there was has been merged to the FFVI article thanks to Antaeus Feldspar. Merge whatever might be left and delete. - Lucky 6.9 22:51, 14 Dec 2004 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
David McNally

David McNally may refer to:

 * David McNally (director) (born 1960), English film director
 * David McNally (football), former chief executive of Norwich City F.C.
 * David McNally (academic) (born 1953), Canadian political scientist
 * Dave McNally (1942–2002), American baseball player

title: David McNally


text:
43rd New Zealand Parliament

The 43rd New Zealand Parliament was a term of the Parliament of New Zealand. Its composition was determined by the 1990 elections, and it sat until the 1993 elections.

The 43rd Parliament saw the beginning of the fourth National Party government, with the Labour Party failing to win a third term in office. The 43rd Parliament was heavily dominated by National, which controlled nearly seventy percent of the seats. Only one minor party, Jim Anderton's NewLabour, was present at the beginning of the 43rd Parliament. Later, NewLabour would join with several unrepresented parties to form the Alliance, which would gain two additional seats when two National MPs defected. Another National MP, Winston Peters, would also break away from his party, becoming an independent.

The 43rd Parliament consisted of ninety-seven representatives, the same as the previous Parliament. All of these representatives were chosen by single-member geographical electorates, including four Māori electorates.

Overview of seats
The table below shows the number of MPs in each party following the 1990 election and at dissolution:

Notes
 * Jim Anderton, Leader of the NewLabour Party merged the party into the newly founded Alliance party.
 * The Working Government majority is calculated as all Government MPs less all other parties.

By-elections during 43rd Parliament
There were a number of changes during the term of the 43rd Parliament.

Summary of changes during term

 * Jim Anderton, the sole MP for the NewLabour Party, merged his party with several others to form the Alliance in 1991. Anderton was thereafter recorded as an Alliance MP rather than a NewLabour MP.
 * Robert Muldoon, the National Party MP for Tamaki and a former Prime Minister of New Zealand, quit Parliament on 17 December 1991. His departure prompted a by-election in Tamaki early the following year — it was won by Clem Simich, also of the National Party.
 * Gilbert Myles and Hamish MacIntyre, the National Party MPs for Roskill and Manawatu, respectively, quit their party in 1992. They established a small group Liberal Party, which they eventually merged into the Alliance.
 * Fran Wilde, the Labour Party MP for Wellington Central, quit Parliament in 1992 to become Mayor of Wellington. Her departure prompted a by-election in Wellington Central in December — it was won by Chris Laidlaw, also of the Labour Party.
 * Cam Campion, the National Party MP for Wanganui, announced his resignation from the party on 3 March 1993. He accused the party of attempting to rig the reselection process against him. Campion remained an independent for the remainder of the term.
 * Winston Peters, the National Party MP for Tauranga, resigned from both his party and his seat on 18 March 1993. His departure prompted a by-election in Tauranga in April — Peters contested and won it as an independent candidate. Later, he would found the New Zealand First party.
 * Myles left the Alliance to join Peters in New Zealand First.

title: 43rd New Zealand Parliament


text:
Mitsubishi Sirius engine

The Mitsubishi Sirius or 4G6/4D6 engine is the name of one of Mitsubishi Motors' four series of inline-four automobile engines, along with Astron, Orion, and Saturn.

The 4G6 gasoline engines were the favoured performance variant for Mitsubishi. The 4G61T powered their Colt Turbo, while the 4G63T, first introduced in the 1980 Lancer EX 2000 Turbo, went on to see service in the Sapporo and Starion coupés during the so-called "turbo era" of the 1980s, before creating for itself an illustrious motorsport heritage as the powerplant under the hood of the World Rally Championship-winning Lancer Evolution. A UK-market Evo known as the FQ400 had a 400 bhp version of the Sirius, making it the most powerful car ever sold by Mitsubishi.

The 4D6 diesel engines supplemented the larger 4D5. Bore pitch is 93 mm.

4G61 (1.6 liters)
The 4G61 displaces 1595 cc with bore/ full length stroke of 82.3x75 mm. This engine was always DOHC 16-valve and used either Multi-point (MPFI) or Electronic Control (ECFI) fuel injection. A turbocharged version was also produced for the Mirage and Lancer. Unlike the other Sirius motors, the 4G61 does not have balance shafts.

Performance
(late) 160 PS at 6000 rpm and 22.5 kgm of torque at 2500 rpm.
 * 4G61 105 hp at 6100 rpm.
 * 4G61T (USA/Canada only) 135 hp at 6000 rpm and 191 Nm of torque at 3000 rpm.
 * 4G61T (Japan, early) 145 PS at 6000 rpm and 21.0 kgm of torque at 2500 rpm.

Applications

 * 1988–1992 Mitsubishi Mirage / Mitsubishi Colt (MPFI)
 * 1988–1992 Dodge Colt / Plymouth Colt
 * 1988–1992 Eagle Summit
 * 1992–1995 Hyundai Elantra

4G62 (1.8 liters)
The larger 1.8 L 4G62 was an SOHC 8-valve unit for longitudinal rear-wheel drive and all-wheel drive use. With a bore and stroke of 80.6 x, it displaces 1795 cc. It was available either in carburetor form, multi-point fuel injection, or ECI Turbo as found in the Lancer EX 1800GSR or 1800GT, and Cordia GSR.

Applications

 * 1980–1987 Mitsubishi Lancer EX 1800GSR or 1800GT (A175A)
 * 1981–1986 Mitsubishi Delica/L300/Express
 * 1983–1987 Mitsubishi Chariot HR
 * 1983–1989 Mitsubishi Cordia
 * 1983–1989 Mitsubishi Tredia
 * 1984–1988 Mitsubishi Galant/Eterna

4G62T
Turbocharged version of the 4G62

4G63/G63B (2.0 liters)
The 4G63 was a 1997 cc version.

Bore x stroke is 85x88 mm SOHC and DOHC were produced. Both versions were available in either naturally aspirated and turbocharged form. For front-wheel drive applications, the turbocharged Sirius' name was changed to "Cyclone Dash". As fitted to the fifth generation Galant 200 PS JIS gross were claimed - the output claims later shrank to 170 PS - for the turbocharged and intercooled "Sirius Dash 3x2 valve" engine. This version could switch between breathing through two or three valves per cylinder, to combine high top-end power with low-end drivability as well as allowing for economical operation. It was a modification of Mitsubishi MCA-Jet technology which used a secondary intake valve to inject air into the engine for more efficient emissions control. The DOHC version was introduced in 1987 in the Japanese market Galant, and came in turbocharged or naturally aspirated form. It is found in various models including the 1988-92 Mitsubishi Galant VR-4, the U.S. market 1990-1999 Mitsubishi Eclipse, and the Mitsubishi Lancer Evolution I-IX. Later versions also received Mitsubishi's variable valve timing system, MIVEC.

A SOHC carbureted eight-valve version (engine code G63B) was also available in Mitsubishi's pickup trucks (L200, Strada, Mighty Max, Dodge Ram 50) from the eighties until the mid-nineties. It produces 92 hp at 5500 rpm in European trim (1989). The SOHC version was also used in Mitsubishi Galant models until 1993. It has 76 kW of output and 157 Nm of torque at 4,750 rpm.

Also, a SOHC version was produced until the late 90s and early 2000s and was used in Mitsubishi cars like the Montero and the 2.0 L 2-door Pajero with an output of 101 kW at 4700 rpm. Also the N33 and N83 Space Wagons and Galant (UK market) received the 4G63, in single-cam sixteen-valve format. A similar version, with 100 PS, was also used in some light duty Mitsubishi Canters from 1997 on.

The Mitsubishi Eclipse, Eagle Talon and Plymouth Laser introduced the DOHC turbocharged intercooled version to the U.S. in 1989 through Diamond Star Motors, a joint venture between Mitsubishi Motors and the Chrysler Corporation. From 1990 to late April 1992 came thicker connecting rods and the use of six bolts to secure the flywheel to the crankshaft; May 1992 to 2006 Evolution versions have lighter rods and use seven bolts to secure the flywheel to the crankshaft. They are referred to as the "six bolt" and "seven bolt" engines, respectively.

Output for the 2003 US Mitsubishi Lancer Evolution is 202 kW at 6500 rpm with 370 Nm of torque at 3500 rpm. It has a cast iron engine block and aluminium DOHC cylinder head. It uses multi-point fuel injection, has four valves per cylinder, is turbocharged and intercooled and features forged steel connecting rods. The final version of the engine was found in Lancer Evolution IX. It was equipped with Mitsubishi's variable valve timing system, MIVEC. This version also had a revised turbocharger, extended reach spark plugs, two-piece rings.

A SOHC 16 valve turbocharged version called 4G63S4T is produced by Shenyang Aerospace Mitsubishi Motors Engine Manufacturing (SAME) in Shenyang, China, producing a peak power of 130 kW and a peak torque of 253 Nm for most applications, and rated 140 kW in some applications. This version is equipped with a TD04 turbocharger.

Racing
Its turbocharged variant, 4G63T (also sometimes referred to simply as the 4G63), has powered Mitsubishi vehicles in World Rally Championships (WRC) for years in the Lancer EX 2000 Turbo, Galant VR-4, Lancer Evolution, Carisma GT, and Lancer WRC04. It was the powerplant of the Lancer Evolution when Tommi Mäkinen won his four consecutive WRC championships in his Lancer. MHI and T-4 turbos were both used as power for these engines. A 1.7L variant of the 4G63 was also used in a custom made hill-climb a DDR Motorsport DDR Grullón GT4 made by Komvet Racing.

Applications

 * 1980–2003 Mitsubishi Galant
 * 1981–1987 Mitsubishi Lancer EX 2000 Turbo
 * 1982–1987 Mitsubishi Starion
 * 1983–1988 Mitsubishi Cordia
 * 1983–1988 Mitsubishi Tredia
 * 1983–1992 Dodge Colt Vista
 * 1983–1998 Mitsubishi Chariot
 * 1983–1989 Mitsubishi L200/Mighty Max
 * 1985–1998 Mitsubishi Delica
 * 1987–1989 Dodge Ram 50
 * 1989–1992 Eagle Vista Wagon
 * 1990–1998 Eagle Talon
 * 1990–1999 Mitsubishi Eclipse
 * 1990–1994 Plymouth Laser
 * 1992–2007 Mitsubishi Lancer Evolution
 * 1993–1998 Mitsubishi Pajero
 * 1994–1998 Mitsubishi RVR
 * 1996–1999 Proton Perdana
 * 1997–2000 Mitsubishi Canter
 * 1998-2007 Mitsubishi Adventure Mitsubishi Freeca Mitsubishi Jolie
 * 1999–2005 Mitsubishi Dion
 * 2000-2006 Mitsubishi Kuda
 * 2001-2014 Mitsubishi Savrin
 * 2002–200? Mitsubishi Lancer
 * 2003–2005 Mitsubishi Airtrek
 * Hyundai production - also called Hyundai Sirius engine

 * 1987–1988 Hyundai Stellar (engine code G4CP)
 * 1992–2005 Hyundai Sonata (engine code G4CP)
 * 1998–2003 Hyundai Santamo (engine code G4CP)
 * 2000–2008 Hyundai Santa Fe (engine code G4JS)
 * 1999-2003 Hyundai Trajet (engine code G4JP)
 * 2000–2004 Kia Joice (engine code G4CP)
 * 2000–2005 Kia Optima/Magentis (engine code G4JP)
 * Chinese production

 * 2004–2010 Brilliance BS6
 * 2006 Brilliance BS4
 * 2007–2015 Great Wall Coolbear
 * 2009–2012 Great Wall Haval H3
 * 2009 Landwind X6
 * 2011–present Landwind X8 4X2 2.0
 * 2011–2013 Emgrand EC8
 * 2014–2016 Zotye T600
 * 2015 BAW Yusheng
 * 2016–2017 Landwind X7
 * 2016–2021 Zotye T700
 * 2017–2019 Zotye SR9
 * 2018 Beijing BJ2022 Brave Warrior

4G64 (2.4 liters)
The 4G64 is the second largest variant, at 2351 cc. Early models were 8-valve SOHC, but a later 16-valve SOHC and DOHC version was also produced. All used MPFI and had a bore and stroke of 86.5x100 mm. The 4G64 was later also available with gasoline direct injection. Output varies between 155 hp at 5,250 rpm with 163 lbft of torque at 4,000 rpm in the Mitsubishi L200 and 152 hp at 5,500 rpm with 163 lbft of torque at 4,000 rpm in the Chrysler Sebring/Stratus. The Chrysler version features fracture-split forged powder metal connecting rods. The DOHC and SOHC 16-valve 4G64 are interference engines, while the SOHC 8-valve 4G64 is a non interference engine. From March 1996 an LPG version with 115 hp at 5,000 rpm was available in the Mitsubishi Canter.

The 4G64 is a very popular engine in China, where it is still used on the Changfeng Lièbào, a series of cars based on the Mitsubishi Pajero V20 from 2002 to 2021, and the Soueast Delica based on the Mitsubishi Delica van from 1996 to 2013. The 4G64 engine has been produced by Shenyang Aerospace Mitsubishi Motors Engine Manufacturing (SAME), in Shenyang, China where it was assembled through semi-knockdown kits in August 1998 and complete knockdown kits in September 1999. Regular assembling of the engines took place in April 2000. The Chinese market Ford Transit and its successor, the JMC Teshun use the 4G64 engine as a standard petrol option unlike the international version which uses regular Ford engines.

Applications

 * 1983–1992 Dodge Colt Vista (AWD only)
 * 1986–1998 Hyundai Grandeur
 * 1986–2005 Mitsubishi Triton
 * 1987–1990 Mitsubishi Sapporo
 * 1988–2018 Mitsubishi Delica/Van
 * 1989–1991 Hyundai Sonata
 * 1990–present Mitsubishi L200
 * 1990–1992 Dodge Ram 50
 * 1990–1996 Mitsubishi Mighty Max
 * 1993–1997 Mitsubishi Chariot
 * 1993–2003 Mitsubishi Space Wagon
 * 1996–1999 Mitsubishi Eclipse
 * 1996–1998 Mitsubishi Magna (codenamed 4G64-S4 and fitted to the TE-TF series)
 * 1996–2003 Mitsubishi Galant (GDI, European market)
 * 1997–1999 Mitsubishi Montero Sport (North American, ES model)
 * 1998–2005 Mitsubishi Montero (V11 - 2 door) Latin America version
 * 1998–2003 Mitsubishi Space Wagon
 * 1999–2005 Hyundai Sonata
 * 2000–2005 Kia Optima
 * 2000–2005 Mitsubishi Eclipse
 * 2001–2004 Dodge Stratus Coupe
 * 2001–2006 Hyundai Santa Fe
 * 2001 Mitsubishi Airtrek
 * 2002–2021 Changfeng Liebao (a series of cars based on the Mitsubishi Pajero V20 from China)
 * 2003-2006 Kia Sorento 2.4i Manual
 * 2003 Mitsubishi Outlander
 * 2004 Brilliance BS6
 * 2004-2006 Derways Cowboy
 * 2004–2006 Chery Eastar
 * 2004–2015 Hyundai Terracan
 * 2005–2009 Great Wall Hover (X240 and V240)
 * 2005 Mitsubishi Zinger
 * 2007 Landwind X6
 * 2008–2015 Chery V5
 * 2006–present Ford Transit/JMC Teshun (Chinese market)

4G64T
Turbocharged version of the 4G64.

4D65 (1.8 liter diesel)
Known as the "Sirius Diesel", the 4D65 has the same dimensions as the 4G62 1795 cc. It was available either naturally aspirated or turbocharged (with an air-to-air intercooler), and was used in most Mitsubishi diesel passenger cars in the eighties and beginning of the nineties. It was developed specifically to be transversally installed in front-wheel-drive cars, unlike the preceding 4D5-series which remained in production for commercial vehicles. The 1.8 TD power figures are comparable to those of the 22 percent larger, 2.3 liter 4D55, with more low-down torque and while being much smoother. The cast-iron block was typical for Mitsubishi, but unusual for diesel engines, in being equipped with balance shafts. A number of installations combined this engine with four-wheel-drive.

Applications

 * 4D65 (naturally aspirated)

 * 1983–1987 Mitsubishi Mirage/Colt/Lancer (C14)
 * 1985–1992 Mitsubishi Mirage/Lancer Van/Wagon (C14/C34)
 * 1987–1991 Mitsubishi Mirage/Colt/Lancer (C64/C74)

 * 4D65T (turbocharged)

 * 1983–1989 Mitsubishi Galant/Galant Σ/Eterna Σ (E14)
 * 1984–1991 Mitsubishi Chariot/Space Wagon (D09W)
 * 1987–1992 Mitsubishi Galant/Eterna (E34)
 * 1988–1991 Mitsubishi Lancer (C74, 4WD sedan only)
 * 1991–1995 Mitsubishi Lancer/Mirage/Libero (CB7, CD7)

4G67 (1.8 liters)
The 16-valve DOHC 4G67 displaced 1836 cc. Bore x Stroke: 81.5x88 mm

Applications

 * 1989–1992 Colt/Lancer 1.8 GTI (C58A/C68A)
 * 1989–1992 Mitsubishi Galant/Eterna (E35A)
 * 1993–1995 Hyundai Elantra, this engine was called G4CN by Hyundai

4D68 (2.0 liter diesel)
Known as the "Sirius Diesel", the 4D68 version displaces 1998 cc. It is fitted with a 93 mm stroke crankshaft and the cylinder bore diameter is 82.7 mm. This engine uses pistons with a static compression ratio of 22.4:1 and piston pins are 25 mm OD. It was available either naturally aspirated or turbocharged, and replaced the 4D65 as Mitsubishi's "go-to" diesel.

 * Type : Diesel engine
 * Number of cylinders: Inline 4
 * Combustion chamber: Swirl chamber
 * Lubrication system: Pressure feed, full-flow filtration
 * Oil pump type: External gear type
 * Cooling system: Water-cooled
 * Water pump type: Centrifugal impeller type
 * EGR type: Single type
 * Fuel system: Electronic control distributor-type injection pump
 * Supercharging: Turbocharger
 * Rocker arm: Roller type

Applications

 * 1991-1996 Mitsubishi Mirage/Colt
 * 1991-1996 Mitsubishi Lancer/Libero
 * 1992-1997 Mitsubishi Chariot/Space Wagon
 * 1992-1999 Mitsubishi RVR/Space Wagon
 * 1996-2000 Mitsubishi Galant/Galant Wagon (Legnum)
 * 1996-1999 Mitsubishi Lancer/Libero
 * 1997-2002 Mitsubishi Mirage/Colt
 * 1995-2000 Proton Wira 2.0D
 * 2007-2008 Mitsubishi Triton/L200

4G69 (2.4 liters)
The 4G69 is a 2378 cc version built in Shiga, Japan and Shenyang, China. Bore and stroke is 87x100 mm. Output is 120 kW at 5750 rpm (160 in the Sportback Wagon) with 219 Nm of torque at 3500 rpm. It has a cast iron engine block (later switch to aluminum block) and an aluminum SOHC cylinder head. It uses multi-point fuel injection, has 4 valves per cylinder with roller followers and features forged steel connecting rods, a one-piece cast camshaft, and a cast aluminum intake manifold. The 4G69 incorporates Mitsubishi's MIVEC Variable Valve Timing technology.

Mitsubishi ceased any further development and production of Sirius engine after 2012 model year, and its Chinese joint-venture, Shenyang Aerospace Mitsubishi Motors Engine Manufacturing Co., is now the only one producing 4G69 engines. They are used by Chinese manufacturers only, but have been updated to use an aluminum block while adding a timing chain.

Applications

 * 2003–2008 Mitsubishi Pajero Sport (China)
 * 2003–2011 Mitsubishi Grandis
 * 2004–2007 Mitsubishi Lancer
 * NB: From 2005 a slightly detuned version developing 115 kW and 220 Nm is used across the entire Lancer range in Australia.

 * 2004–2006 Mitsubishi Outlander
 * 2004–2012 Mitsubishi Galant
 * 2004-2014 Mitsubishi Savrin
 * 2006–2012 Mitsubishi Eclipse
 * 2008–present Mitsubishi Zinger (automatic models only)
 * 2006–2012 Great Wall Wingle 3
 * 2007–2010 Great Wall Haval H3
 * 2009–2020 Great Wall Haval H5
 * 2010–present Great Wall Wingle 5
 * 2011–2013 BYD S6
 * 2012–present JMC Yuhu
 * 2011–2014 Emgrand EC8
 * Of further note, the Great Wall Haval uses a completely detuned variant offering only 100 kW and 200 Nm
 * 2014–present Great Wall Wingle 6
 * 2009–2015 Great Wall Coolbear
 * 2015–2016 Landwind X6
 * 2006–2013 Zhongxing Landmark
 * 2014–present Maxus G10
 * 2019–present CMC Mitsubishi Delica Van/Pickup
 * 2019–present Maxus T70

4G6A
A SOHC 16 valve turbocharged engine similar to 4G63S4T, produced by SAME in Shenyang, China, utilizing a 4G63 shortblock destroked to a displacement of 1798 cc.
 * Displacement: 1,798 cc
 * Bore × Stroke (mm): 85 × 79.2
 * Compression ratio: 9.4:1
 * Multi-point intake manifold injection
 * Turbocharger model: TD04
 * Peak power: 120 kW
 * Peak torque: 231 Nm at 2,500 ~ 5,000 rpm
 * Minimum fuel consumption rate: 255 g/kw·h

4K1 series
The 4K1 New MIVEC series is based on 4G6 shortblock but mated to a redesigned SOHC 16 valve head with VVL and MIVEC technology. Combustion chambers and piston surfaces were re-engineered to improve fuel economy by lowering friction. All 4K1 models are naturally aspirated and are currently produced by SAME in Shenyang, China.

4K10 (1.8 liters)
Destroked 4G63 shortblock, same as 4G6A but with the new SOHC MIVEC head.
 * Displacement: 1,798 cc
 * Bore × Stroke (mm): 85 × 79.2
 * Compression ratio: 10.5:1
 * Multi-point intake manifold injection
 * Peak power: 100 kW at 6,000 rpm
 * Peak torque: 170 Nm at 4,000 rpm
 * Minimum fuel consumption rate: 245 g/kw·h
 * No balance shaft

4K11 (2.0 liters)
Utilized 4G63 shortblock.
 * Displacement: 1,997 cc
 * Bore × Stroke (mm): 85 × 88
 * Compression ratio: 10.5:1
 * Multi-point intake manifold injection
 * Peak power: 110 kW at 6,000 rpm
 * Peak torque: 190 Nm at 4,000 rpm
 * Minimum fuel consumption rate: 245 g/kw·h
 * Optional balance shaft

4K12 (2.4 liters)
Utilized 4G69 shortblock.
 * Displacement: 2,378 cc
 * Bore × Stroke (mm): 87 × 100
 * Compression ratio: 10.5:1
 * Multi-point intake manifold injection
 * Peak power: 120 kW at 6,000 rpm
 * Peak torque: 225 Nm at 4,000 rpm
 * Minimum fuel consumption rate: 245 g/kw·h
 * Standard balance shaft

All 4K1 models are available for both longitudinal and transverse applications.

4K2 series
In 2017, Mitsubishi launched a new series of gasoline inline-four engines called the 4K2 series. Originally consisting of three models, 4K20, 4K21 and 4K22, they are available in naturally aspirated as well as turbocharged versions. This new design is based on the 4G6 shortblock, mated to a newly designed DOHC 16-valve head with MIVEC technology.

The 4K2 series is also produced by SAME in Shenyang, China.

4K20
Destroked 4G63 shortblock, same as 4G6A but with the new DOHC head. Only available as a turbocharged model (4K20D4T).
 * Displacement: 1,798 cc
 * Bore × Stroke (mm): 85 × 79.2
 * Compression ratio: 9.5:1
 * Multi-point intake manifold injection
 * Peak power: 128 kW at 5,500 rpm
 * Peak torque: 250 Nm at 2,000 ~ 4,800 rpm
 * Minimum fuel consumption rate: 251 g/kw·h
 * Optional balance shaft
 * Transverse application only

4K21
4G63 shortblock, available as a turbocharged model (4K21D4T) or two naturally aspirated models (4K21D4M & 4K21D4N)
 * Displacement: 1,997 cc (4K21D4T & 4K21D4M) 2,019 cc (4K21D4N)
 * Bore × Stroke (mm): 85 × 88 (4K21D4T & 4K21D4M) 85 × 89 (4K21D4N)
 * Compression ratio: 9.4:1 (4K21D4T) 10.5:1 (4K21D4M & 4K21D4N)
 * Multi-point intake manifold injection
 * Peak power: 150 kW at 5,600 rpm (4K21D4T) 110 kW at 6,000 rpm (4K21D4M) 117 kW at 6,000 rpm (4K21D4N)
 * Peak torque: 280 Nm at 2,000 ~ 4,800 rpm (4K21D4T) 195 Nm at 4,000 rpm (4K21D4M) 201 Nm at 4,000 rpm (4K21D4N)
 * Minimum fuel consumption rate: 250 g/kw·h (4K21D4T) 242 g/kw·h (4K21S4M) 244 g/kw·h (4K21D4N)
 * Optional balance shaft for naturally aspirated models (4K21D4M & 4K21D4N), standard on the turbocharged model (4K21D4T)
 * Longitudinal application only

4K22
4G69 shortblock, available as a turbocharged model (4K22D4T) or a naturally aspirated model (4K22D4M)
 * Displacement: 2,378 cc
 * Bore × Stroke (mm): 87 × 100
 * Compression ratio: 9.6:1 (4K22D4T) 10.5:1 (4K20D4M)
 * Multi-point intake manifold injection
 * Peak power: 160 kW at 5,600 rpm (4K22D4T) 118 kW at 6,000 rpm (4K22D4M)

 * Peak torque: 320 Nm at 2,400 ~ 4,000 rpm (4K22D4T) 218 Nm at 4,000 rpm (4K22D4M)
 * Standard balance shaft
 * Longitudinal application only

Applications

 * 2020 Peugeot Landtrek

4K31
In 2022, Mitsubishi (SAME in Shenyang, China) launched the new generation of in-Line 4 cylinder Turbo supercharged gasoline direct injection engine (TGDI). It also has six technologies, including variable displacement oil pump, double vortex turbocharger, intake and exhaust door timing variable, high compression ratio, lightweight design, mute technology, etc. It is more efficient and more fuel-efficient.

Displacement: 1,997 cc (4K31TD)
 * Bore × Stroke (mm): 85 × 88
 * Compression ratio: 10.5:1
 * Peak power: 168 KW (225 hp, 228 PS)
 * Peak torque: 360 N.m

Applications:

 * 2022 Zhengzhou Nissan Rich 7 (Pickup Ruiqi 7).
 * 2022 Zhengzhou Nissan Palaso/Palasso.
 * 2023 Zhengzhou Nissan New Paladin (based on Nissan Terra).

title: Mitsubishi Sirius engine


text:
Lamkin

"Lamkin" or "Lambkin" is an English-language ballad. It gives an account of the murder of a woman and her infant son by a man, in some versions, a disgruntled mason, in others, a devil, bogeyman or a motiveless villain. Versions of the ballad are found in Scotland, England and the US.

According to Roud and Bishop (2012): "Lambkin" is not one of the major league Child ballads in terms of popularity, but it was widely known in England and Scotland, and even more so in North America. ... The central character's name varies considerably, including, in just the English versions 'Lambkin', 'Lamkin', 'Lincoln', and 'Limkin', and he is various referred to as 'Long', 'Bold', 'Cruel' and 'False'.

They cite the analysis of Anne Gilchrist, who identified two threads: one Scottish, which retained the mason narrative; one Northumbrian, which lost the mason in early versions, thus encouraging singers to supply a different back-story. Versions collected in England stem from the Northumbrian thread.

A bogeyman
Other versions follow the same basic story, but the antagonist has many different names, among them "Long Lonkin", "Balankin", "Lambert Linkin", "Rankin", "Long Lankyn", and "Lammikin". Later versions lose the opening of the story, which explains that Lamkin is a mason who has not been paid; in these, Lamkin becomes a sort of a bogeyman who dwells in the wild places; the lord, before leaving, warns against him:

 * Says milord to milady as he mounted his horse,
 * "Beware of Long Lankin that lives in the moss."
 * Says milord to milady as he went on his way,
 * "Beware of Long Lankin that lives in the hay."

These versions add peculiar incidents that add to the grisliness of the crime. Lamkin and the nursemaid collect the baby's blood in a basin which, along with the idea that the name Lamkin or Lammikin indicates the murderer was pale skinned and, therefore, perhaps a leper who sought to cure himself by bathing in the blood of an innocent collected in a silver bowl, a medieval cure.

Performances

 * A version titled "Bolakins" was recorded as sung by Mrs. Lena Bare Turbyfill in 1939, Library of Congress
 * The song has been recorded as "Long Lankin" on But Two Came By (1968) by Martin Carthy.
 * The song "Bo Lamkin" was recorded by Appalachian folk musician Frank Proffitt.
 * In 1973 Northumbrian folk group The High Level Ranters recorded it as "Long Lonkin" on their album A Mile To Ride.
 * Steeleye Span recorded it as "Long Lankin" on Commoners Crown (1975).
 * Dave Burland recorded "Lamkin" on his album You Can't Fool The Fat Man (1979) with Nic Jones.
 * The Neofolk band Fire + Ice recorded "Long Lankin" on their album Gilded By The Sun (1992).
 * Tinkerscuss perform and recorded a version as Long Lankin on their album "Stonedancing" https://store.cdbaby.com/cd/tinkerscuss2
 * Jim Moray recorded a version as "Long Lankin" on his album In Modern History (2010).
 * A version was recorded by English traditional singer Ben Butcher as "Cruel Lincoln" in 1955 and issued on The Voice of the People Vol, 3 in 1988.
 * The song "Lambkin" is included on the studio album Smoke of Home, the second album by the band Megson, released in 2007.
 * The Wainwright Sisters also included a recording of Long Lankin on their 2015 album Songs in the Dark.
 * Blackbeard's Tea Party's 2013 album Whip Jamboree features a version of the ballad.
 * For her 2016 album Lodestar, English folk singer Shirley Collins recorded a version of "Cruel Lincoln," which draws from the Ben Butcher version.
 * Classical composer and librettist Fleur de Bray set the story of Long Lankin as an opera, which was premiered in August 2013 at the acclaimed London Tête à Tête Opera Festival.
 * The 2018 Adult Swim series The Shivering Truth features variations of the ballad (titled "Long Lankin" in this case) sung by different artists over the end credits of every episode.
 * Martin Simpson released a version of this ballad entitled "Beaulampkin" on compilation of Fernie Court Management Ltd.
 * Seventeen field-recordings of the ballad, spanning 1934–2021, were curated by Derek Piotr and released by Death is Not the End, in 2022.

In literature
The ballad, as Long Lonkin, was taken from a friend by Letitia Elizabeth Landon and published in her Fisher's Drawing Room Scrap Book, 1835.

The song was referenced in the title of the short story collection, Long Lankin, by John Banville. The American poet Robert Lowell also referenced the song in the title of his Pulitzer Prize-winning collection of poetry Lord Weary's Castle (1946). The song inspired the young-adult novel Long Lankin (2011) by Lindsey Barraclough.

A sadistic character named Lankin appears as a member of the Fairy Queen's court in Terry Pratchett's Lords and Ladies.

Long Lankin appears in Jane Yolen and Midori Snyder's book Except The Queen.

title: Lamkin


text:
Christmas shearwater

The Christmas shearwater or aoū  (Puffinus nativitatis) is a medium-sized shearwater of the tropical Central Pacific. It is a poorly known species due to its remote nesting habits, and it has not been extensively studied at sea either.

It is one member of a very ancient lineage of the small Puffinus species. Its only close living relative is the Galápagos shearwater (P. subalaris).

Taxonomy
The species was described and given its current binomial name by the American naturalist Thomas Hale Streets in 1877. A genetic analysis using mitochondrial DNA has shown that the closest living relative is the Galápagos shearwater (Puffinus subalaris).

Description
The Christmas shearwater is a slender-bodied shearwater, about 36 cm long, with a wingspan of around 75 cm, and weighs around 350 g. It has dark plumage all over, generally blackish-grey with a rusty-brown tinge, slightly paler on the underside of the bird, and with some small edging of white under the chin and pale fringes to the upperwing coverts. It has brown-grey feet and a dark bill and eyes. Both sexes are alike, as are the young after fledging. Nestlings are covered in dark grey down feathers.

The species closely resembles the sooty (Puffinus griseus) and short-tailed shearwaters (P. tenuirostris), but has dark brown underwings and is smaller. The short tail of the Christmas shearwater does not appear blunt except when spread, but in flight usually tapers to a point, enhanced by the feet which protrude beyond the tail-tip. It often flies in a leisurely way like the related Procellariidae, and thus can be mistaken for a petrel. In particular, it can appear similar to the extremely rare Fiji petrel (Pseudobulweria macgillivrayi), a gadfly petrel-like relative of the shearwaters. The two species share a similar morphology and colouration, but the bulbous head and rather thin long bill – typical for shearwaters – distinguish P. nativitatis from the slim-headed thick-billed Fiji petrel.

Distribution and habitat
The Christmas shearwater nests on remote islands of the Central Pacific: the Northwestern Hawaiian Islands, Tuamotu, the Marshall Islands, Kiritimati (for which the species is named) and Sala-y-Gómez. It has become locally extinct on a number of islands, including Wake Island. Outside of the breeding season it ranges across the Pacific, having been recorded off the coast of Mexico and Guatemala in the east, and Bonin Islands in the west. Further south it is rare, having been recorded off Fiji only twice (one time in early to mid-May).

Diet and feeding
Like its relatives it feeds at sea, predominantly on squid, and fish, mostly flying fish (Exocoetidae) and goatfish (Mullidae). It is highly pelagic and is dependent on predatory fish such as tuna driving prey to the surface. As mentioned above, it does not only have the dramatic stiff-winged "shearing" (dynamic soaring) flight technique which gave the shearwaters their common name. In addition to it, it may use the plesiomorphic flight technique of petrels and similar Procellariidae, moving about with slow, leisurely wingbeats.

Breeding
The Christmas shearwater nests on sandy islands with good cover. It nests on the surface, underneath dense cover (such as naupakas, Scaevola), or under rock outcroppings. It lays one white egg, the timing of laying varying from island to island, on some islands breeding throughout the year. The egg is incubated for around 50 days. The time taken to fledge varies depending on the season, ranging from 60 to 100 days.

Status and conservation
Although few specific studies have been conducted on the Christmas shearwaters, petrels and shearwaters are threatened worldwide by fishing, ingestion of plastic waste, and habitat degradation. For example, on Laysan Island the introduced rabbits degraded the scrub cover, leaving adults, chicks and eggs vulnerable to overheating, and introduced black rats took eggs and chicks. In 1985, the population on Sala-y-Gómez, a nature sanctuary, was estimated at 5,000. With its wide range and considerable numbers, the Christmas shearwater is considered a species of least concern by the IUCN.

title: Christmas shearwater


text: File:Australia satellite plane.jpg

title: File:Australia satellite plane.jpg


text: User talk:128.175.77.23

title: User talk:128.175.77.23