THERMOSTATS FOR MOLECULAR FLUIDS UNDERGOING SHEAR-FLOW - APPLICATION TO LIQUID CHLORINE

In this article we show that atomic thermostats which have been used i n the past for nonequilibrium molecular dynamics (NEMD) simulations of molecular fluids were incorrectly formulated. The error stems from an incorrect assumption made about the form of the streaming angular vel ocity. This assumption is incorrect even in the linear regime. One spu rious effect of this atomic thermostat is the generation of a nonsymme tric pressure tenser. We outline a general method, based on a variatio nal principle, for calculating the position and orientation dependent streaming velocity. Using this streaming velocity we develop an atomic thermostat for molecular fluids which does not bias the positional or orientational distribution functions for the fluid. The new atomic th ermostat is validated in NEMD simulations of liquid chlorine undergoin g planar Couette flow. (C) 1995 American Institute of Physics.