Nearest neighbour contributions to the atom-atom pair distribution functions of liquid iodine and chlorine

Abstract

The atom-atom pair distribution functions g _a-a(r) of liquid iodine and chlorine are obtained from computer simulations which exploit anisotropic site potential models. The analysis of g _a-a(r) in terms of microscopic configurations and nearest neighbours is performed. It is shown that the warped ‘L’ and the very canted parallel configurations due to nearest neighbours are able to give a significant contribution to g _a-a(r) at interatomic distances of 7 or 8 Å where the next nearest neighbours dominate. The appearance of three peaks in the simulated g _a-a(r) of liquid iodine, confirmed by recent neutron diffraction measurements, is naturally explained. The shoulder around r = 7 Å present in the g _a-a(r) of liquid Cl₂ is discussed.