Computer simulations of dense molecular fluids

Abstract

Molecular dynamics simulations are reported for ensembles of several models of homonuclear diatomic molecules. The systems were studied all at a single phase point (i.e. at a single value of reduced temperature and density), but with potential functions that varied primarily by changing the strength of the quadrupolar part of the intermolecular interaction. Both translational and rotational motions of single molecules were studied, either by calculation of the autocorrelation functions for velocity or orientation or of the distributions of atomic or molecular displacements. It is shown that the simulations of orientational correlation functions do not correspond well to the predictions of any of the better-known models for reorientation in fluids. It is argued that theories in which the mean square forces and torques play a prominent role should give a better description of these systems than binary collision approaches.

Notes

This work supported in part by grants from the National Science Foundation.