Intermolecular and Surface Forces, 3rd Edition

Chapter 13 Van der Waals Forces between Particles and Surfaces

13.1 Van der Waals Force-Laws for Bodies of Different Geometries: the Hamaker Constant

As we saw in Part I, van der Waals forces play a central role in all phenomena involving intermolecular forces, for while they are not as strong as Coulombic or H-bonding interactions, they are always present and can be important both at small and large separations. Let us begin by deriving the van der Waals interaction energies in a vacuum for pairs of bodies of different geometries. Starting at the simplest level, we shall assume that the interaction is nonretarded and additive. In Chapter 11 we saw that for an interatomic van der Waals pair potential of the form w(r) = −C/r⁶, one may sum (integrate) ...