Effect of Intermolecular Forces on Macromolecular Configurational Changes and on Other Isomeric Equilibria

Abstract

The effect of intermolecular forces on isomeric equilibria (configurational changes in macromolecules are a special case) is investigated. The term corresponding to the second virial coefficient is derived but the method can easily be extended to higher terms. A significant and measurable effect is predicted for (a) isomeric equilibria involving atoms or small molecules or (b) configurational changes in macromolecules at a first-order phase transition or critical point. A negligible effect is predicted for configurational changes in macromolecules otherwise. These conclusions apply to ``proper'' thermodynamic variables only; the end-to-end length r of a random coil is excluded.