MOLECULAR-ORIENTATION AT A VAPOR-LIQUID INTERFACE - THEORETICAL AND COMPUTER-SIMULATION RESULTS FOR A MODEL OF CHLORINE

A first order perturbation theory is used to calculate the density-orientation profile ρ(z1ω1) for the vapor-liquid interfacial region for a fluid of homonuclear diatomic molecules. The intermolecular potential used is a site-site Lennard-Jones model, with the parameters chosen to approximate chlorine. The theoretical results are compared with molecular dynamics results. The molecular dynamics calculations show that the molecules favor an alignment perpendicular to the surface on the liquid side, whereas an alignment parallel to the surface is preferred on the gas side of the dividing surface. The theory predicts both of these qualitative features. The quantitative agreement between theory and simulation is quite good on the liquid side, but is poorer on the gas side of the dividing surface. © 1979 American Institute of Physics.