Talk:Van der Waals force

message: 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)
replies: text: 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)
thread_title:  Misleading description of the repulsive component 

message: 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)
replies: text: The last two paragraphs of the intro are indeed best moved elsewhere.--Ymblanter (talk) 20:44, 15 June 2013 (UTC)
thread_title:  Minor work mentioned without citing more important work 

message: 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)
thread_title:  Link with noble gases 

message: 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)
thread_title:  Forces 

message: 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)
replies: text: 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)

text: 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)
thread_title:  London forces named for Fritz London? 

message: 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)
thread_title:  Merger 

message: 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)
replies: text: 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)

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

message: :"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)
replies: text: 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)
thread_title:  London force only a sub part of VDW 

message: 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)
thread_title:  Shouldn't "oval" be "ellipsoid"? 

message: 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)
thread_title:  Dipole moment of ellipsoid 

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

text: 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)
thread_title:  Hamaker Force Interactions 

message: 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)
thread_title: [[Van der Waals forces]] and [[Intermolecular force]]

message: 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)
replies: text: 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)

text: 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)
thread_title:  Adhesives 

message: 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)
thread_title:  Van der walls forces in rubber 

message: 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)
replies: text: 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)

text: 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)
replies: text: 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)
thread_title:  Nomenclature 

message: 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)
thread_title:  Fraught with Errors 

message: 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)
thread_title:  Needs an intro section 

message: “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)
thread_title:  London forces weaker than permanent dipole-dipole interactions? 

message: 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)
replies: text: Done. But remember that there's no "head author"--anyone can fix errors, including you! --Itub (talk) 10:07, 21 February 2008 (UTC)
thread_title:  Make up your mind about capitalization of Van when it appears in the middle of the sentence. 

message: 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)
thread_title:  Lowercase title 

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

message: 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)
thread_title: equation

message: 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)
thread_title:  Dipole-dipole force 

message: 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)
thread_title:  Gecko research 

message: 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)
thread_title:  Geckos' Mastery of Physical Theory. 

message: 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)
replies: text: 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)
thread_title:  uncited plagiarism 

message: 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)
thread_title:  Instantaneous dipoles? 

message: 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)
thread_title:  Examples 

message: 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)
replies: text: 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)
thread_title:  Proposals for some improvements 

message: 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)
replies: text: sure it is 92.184.124.117 (talk) 11:24, 14 April 2023 (UTC)
thread_title:  The first force 

message: 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)
thread_title:  Spider-Man Reference

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

message: 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)
thread_title:  Cancelling out Van Der Walls forces 

message: 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)
thread_title:  Rewrite