Orientational correlations in the liquid halogens

Abstract

This paper describes the extension of the recently developed Reverse Monte Carlo technique to the problem of molecular liquids. The technique has been applied to available neutron and X-ray diffraction data on the liquid halogens and on liquid nitrogen. The molecular centres structure factors and pair correlation functions have been calculated and the molecular correlation function g(r, θ₁, θ₂, φ) has been expanded as a sum of spherical harmonics. The results show that orientational correlations are largely confined to the nearest neighbour coordination shell. Although these correlations are partly due to geometric factors there is also an increased tendency for the molecules in the heavier halogens to be aligned end to end.