Quantum mode phonon forces between chainmolecules

A phenomenological description of the contributions of phonons to molecular force is developed. It uses an approximation to consider macromolecules as solid continua. The molecular modes of a molecule can then be characterized by a Debye-like description of the partition function. The resulting bimolecular interaction is a truly many-body force that is temperature dependent and can be of the order of 1 eV.

These phonon forces depend on molecular shape, composition, and density. They may therefore also be important for large molecular conformational changes, including the unfolding of chain molecules. For the later case, a significant change in zero-point energy is found. This may be the underlying cause for cold denaturation of proteins. (C) 2001 John Wiley & Sons, Inc.