Intermolecular and Surface Forces, 3rd Edition

9 Nonequilibrium and Time-Dependent Interactions

9.1 Time- and Rate-Dependent Interactions and Processes

So far, time has played little role in our analysis of the forces and energies between molecules. This is because we have always been assuming equilibrium conditions, with the implicit assumption that neither the interaction potential nor the force changes with time, as opposed to distance or location. We have also assumed that the force is independent of the rate or velocity of relative motion of the interacting molecules.

It is not always easy to distinguish between equilibrium and nonequilibrium phenomena. Some equilibrium interactions or conditions can be more readily derived via a dynamic model, as in the case of the retarded van der ...