Molecular glue

Van der Waals forces: a handbook for biologists, chemists, engineers, and physicists  

V Adrian Parsegian  

Cambridge, UK: Cambridge University Press 2006 | 380pp | ?27.99 (SB) | ISBN 0521547784  

Reviewed by Anthony Stone

Van der Waals or dispersion forces provide the universal glue that holds molecules together. Parsegian has provided a user manual that describes their behaviour in many situations. It offers a beginner’s introduction to the ideas, followed by a compendium of formulae for particular cases. At the end there is a more detailed account of the underlying physics. 

The account is almost entirely from the macroscopic point of view, and even the formula for the interaction between atoms, obtained by London in 1930 using quantum mechanics, is here treated as a special case of interaction between conducting spheres, and derived from the Lifshitz formula (1954) for interaction between macroscopic bodies. For molecules, moreover, there are other contributions to the interaction energy that are at least as important as the dispersion energy. Consequently this book is unlikely to find many readers among the biological and chemical community, despite the publishers’ claims. 

The treatment aims to explain the physical ideas in an accessible manner, while giving the mathematical derivations in full detail. 

Units were once a problem in any material involving electromagnetic properties, because different unit systems were used for electric and magnetic properties. The difficulty was resolved by the introduction of the Syst?me Internationale d’Unit?s (SI) more than 40 years ago, but Parsegian panders to hidebound users of the electrostatic unit charge (esu) system (which he calls cgs) by providing formulae in esu as well as in SI (which he calls MKS, although it is in fact rationalised MKS). The result is unnecessarily confusing, because it is a trivial matter to obtain the esu formulae from SI if required.