A quantum multi-mode molecular dynamics approach to the vibrational spectroscopy of solvated hydrogen-bonded complexes

A mixed quantum-classical molecular dynamics method for the dynamics of many coupled vibrational degrees of freedom in a bath of solvent molecules is presented. The theoretical formulation is based on an adiabatic separation between the quantized modes and the remaining classical degrees of freedom and therefore is best suited for high-frequency intramolecular vibrations. The method is of practical relevance to solvated hydrogen-bonded complexes, where the infrared absorption spectra of high-frequency modes are typically subject to strong environmental effects. As a test case, OH stretch mode spectra of hydrogen-bonded methanol complexes dissolved in carbon tetrachloride are computed.