Structural properties of liquid HF: a computer simulation investigation

Monte Carlo simulations of liquid HF have been performed with a newly developed effective pair potential model which can reproduce successfully structural and thermodynamic properties of the liquid at 273 K. A detailed investigation of the structural properties of liquid HF is presented here. Partial pair correlation functions; geometrical and energetic properties of the hydrogen bonds and the topology of the hydrogen bonded clusters are analysed in detail. These results show that the hydrogen bonds, present in liquid HF, are exceptionally short and strong. The preferred geometry of these bonds is linear around the bonding H atoms, whereas the average H ... F-H angle around the acceptor F atom is found to be tetrahedral. More than 80% of the molecules have exactly two hydrogen bonded neighbours, and the dominant form of the hydrogen bonded clusters is the linear chain-like arrangement which contains a few branching points or a cycle. Liquid HF is found to be rather structureless beyond the distance range of the hydrogen bonded neighbours. The results of the present study are in a very good agreement with those obtained by a recent ab initio molecular dynamics simulation.