Vibrational contributions to solute molecular properties obtained through a semiclassical model employing ellipsoidal cavities

A recently proposed semiclassical model for simulating optical properties o f solutions and liquids is extended to encompass vibrational polarizabiliti es. Taking account of both the electronic and vibrational contributions it is shown that the size of an ellipsoidal cavity of pure liquids can be dete rmined in a way that gives consistency between the predicted microscopic an d macroscopic properties. It is found that a good estimate of the vibration al polarizability of the pure liquid can be obtained from experimental data on the molecular, gas phase, infrared (IR) spectrum. The influence of the cavity shapes on the liquid susceptibilities is examined using pure liquid ethanol as a test system. (C) 1999 American Institute of Physics. [S0021-96 06(99)51216-6].