NEAREST NEIGHBOR CONTRIBUTIONS TO THE ATOM ATOM PAIR DISTRIBUTION-FUNCTIONS OF LIQUID IODINE AND CHLORINE

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 angstrom 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 angstrom present in the g(a-a)(r) of liquid Cl2 is discussed.