Configurational and vibrational entropies and molecular relaxation in supercooled water

Abstract

By equating the Adam-Gibbs and Vogel-Fulcher-Tamman equations for the relaxation time, plausible estimates of the temperature-variant size of the cooperatively rearranging region and the energy barrier for cooperative rearrangement were obtained for supercooled water. The excess entropy of water over hexagonal ice is larger than the configurational entropy, a distinction that is often overlooked by assuming that the vibrational entropies of liquid water and hexagonal ice are equal. This allows the relaxation kinetics to be related to the configurational entropy in terms of the Adam-Gibbs equation.