The pressure tensor in an inhomogeneous fluid of non-spherical molecules

Abstract

A general expression for the pressure tensor in an inhomogeneous fluid composed of molecules interacting via non-central, pairwise additive forces is derived. Both planar and spherical surfaces are examined; in each case, expressions for two of the many possible definitions of the pressure tensor (Irving-Kirkwood and Harasima) are obtained and discussed. All definitions of the pressure tensor give the same expression for the surface tension in the planar system; this expression has been previously derived using the virial theorem. The uses of the results of this paper within the context of computer simulation are discussed.