Talk:van der Waals force

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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#Definition 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 <http://www.britannica.com/eb/article-9074766>. “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, [1] had "or Van der Waals forces"; [2] had "called 'Van der Waals' forces"; facebook page [3] 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)

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? AXONOV (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? AXONOV (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)