Analysis of single-molecule dynamics in liquid HF

The center-of-mass velocity autocorrelation function of liquid HF is examined by means of a velocity field approach, originally developed for monatomic liquids and subsequently tested for liquid water. The basic ingredients of the approach (the wavevector-dependent current correlations) are evaluated by computer simulations in a model HF system using a recently developed intermolecular potential. The theory is found to reproduce the relevant features of self-dynamics in HF. The main advantage of the approach is the decomposition of single-molecule motion into longitudinal and transverse contributions, which provides information clarifying the origin of the peculiarities of HF dynamics. A comparison with the results for H2O is presented, with the aim of stressing the different behavior of these two hydrogen-bonded systems.