Intermolecular orientations in liquid acetonitrile: new insights based on diffraction measurements and all-atom simulations

Intermolecular correlations in liquid acetonitrile (CH3CN) have been revisited by calculating orientational correlation functions. In the present approach, hydrogen atoms are included, so that a concept applicable for molecules of (nearly) tetrahedral shape can be exploited. In this way molecular arrangements are elucidated not only for closest neighbours but also extending well beyond the first coordination sphere. Thus a complementary viewpoint is provided to the more popular dipole-dipole correlations. Our calculations are based on large structural models that were obtained by applying diffraction data and partial radial distribution functions from potential-based (all-atom) molecular dynamics simulation simultaneously, within the framework of the Reverse Monte Carlo method.