Liquid dimethyl carbonate: a quantum chemical and molecular dynamics study

A density functional theory based Car-Parrinello molecular dynamics simulation of liquid dimethyl carbonate, an environmentally benign solvent, has been carried out to study its structure and dynamics. Conformational excitations of the molecule have been probed in both its gas and liquid phases. While the cis-cis conformer is the global energy minimum and, thus, the most predominant, at ambient conditions a few percent of molecules are present in the cis-trans conformation as well. The latter possesses a dipole moment of around 4.5 D in the liquid state, a value that is nearly five times as large as that for the cis-cis conformer. Dipole-dipole interactions play a crucial role in the formation of small hydrogen bonded clusters of cis-trans conformers in the liquid. The vibrational spectrum of liquid dimethyl carbonate has been obtained from the trajectory and is shown to agree quite well with available experimental data.