Vibrational spectroscopy and molecular dynamics of solvated methanol tetramer and pentamer Original Research Article

A mixed quantum-classical molecular dynamics study of methanol tetramer and pentamer dissolved in CCl4 is presented. The underlying model is composed of partially flexible methanol molecules interacting with each other and the solvent molecules through standard intermolecular potentials. The high-frequency hydroxyl stretch mode of each solute molecule is treated quantum-mechanically, while classical mechanics is used for rotational and translational degrees of freedom. The theoretical IR absorption spectra for the OH stretch mode fundamental of methanol are discussed in relation to structural data obtained from the molecular dynamics simulation. Cyclic and open conformers are found with an estimated ratio of 6:4 (tetramer) and 7.5:2.5 (pentamer). The H-bond exchange dynamics of open conformers, which differs from that of cyclic conformers, is analyzed.