New six-site acetonitrile model for simulations of liquid acetonitrile and its aqueous mixtures.

A new six site flexible acetonitrile molecular model is developed. The AMBER force field was used for description of intramolecular parameters, the atomic charges were calculated from a high level ab initio theory and finally the Lennard-Jones parameters were tuned to fit the experimental density and evaporation heat. The obtained in this way model reproduces correctly densities of water-acetonitrile mixtures as well as provides qualitative description of the dielectric permittivity and self-diffusion coefficients.