Vibrational energy relaxation of the OH(D) stretch fundamental of methanol in carbon tetrachloride.

The lifetimes of the hydroxyl stretch fundamentals of two methanol isotopomers, MeOH and MeOD, in carbon tetrachloride solvent are calculated through the use of the perturbative Landau-Teller and fluctuating Landau-Teller methods. Examination of these systems allows for insight into the nature of the vibrational couplings that lead to intramolecular vibrational energy transfer. While both systems display energy transfer to nearly degenerate modes, MeOD also displays strong coupling to an off-resonant vibration. The relaxation of MeOH and MeOD occurs through transitions involving a total change in the vibrational quanta of 4 and 3, respectively. We calculate vibrational energy relaxation lifetimes of 4-5 ps for MeOH and 2-3 ps for MeOD that agree well with the experimentally determined values.