Vibrational relaxation in simple fluids: a comparison of experimental results to the predictions of isolated binary collision theory

Abstract

The modeling of the vibrational relaxation of molecules in simple liquids was tested using a number of implementations of isolated binary collision theory. These investigations are valuable for both the knowledge that is gained and because the models are compared to the well studied experimental system of iodine vibrationally relaxing in liquid xenon. The model started with a one-dimensional trajectory calculation in order to predict the transition probability of vibrational relaxation as a function of vibrational energy in the iodine molecule. The density dependence of the bibrational relaxation from experimental and molecular dynamics over a large part of the Lennard-Jones phase diagram are compared to the prediction of a number of implementations. For the most part the simple models are successful, however, problems with the simple models and their implementation are also discussed.