Resonant long-range interactions between polar macromolecules

Motivated by its prospective biological relevance, the issue of resonant long-range interactions between two molecules displaying oscillating dipole moments is reinvestigated within the framework of classical electrodynamics. In particular, our findings shed new light on Frohlich's theory of selective long-range interactions between biomolecules. First, terms of a very long-range kind - which have never been reported so far - are found in the interaction potential, due to field retardation. Second, at variance with a long-standing belief, it is shown that sizable resonant long-range interactions may exist only if the interacting system is out of thermal equilibrium. (C) 2013 Elsevier B.V. All rights reserved.