The structure of liquid methanol: A molecular dynamics study using three-site models

The structure of liquid methanol at 298.15 K is investigated by performing molecular dynamics (MD) simulations in NVE ensemble using two 3-site force field models. The simulated structural results are compared with the recent neutron diffraction (ND) results obtained at the partial pair distribution function (pdf) level by employing H/D substitution on the hydroxyl hydrogen, Ho. Overall agreement is found between the simulated and experimental total intermolecular radial distribution functions (rdfs). The ability of the 3-site model simulations to satisfactorily reproduce experimental X-X (X=C, O or H- a methyl hydrogen) intermolecular partial distribution function, dominated by contributions from the methyl group, demonstrates that the methyl group does not participate in any bonding in the liquid. However, a comparison between the simulated and experimental Ho-Ho and X-Ho functions reveals that discrepancies still exist at a quantitative level.