Molecular dynamics study of the vibrational relaxation of OClO in bulk liquids

The vibrational relaxation of OClO in bulk water, acetonitrile, and ethanol is studied using classical and semiclassical molecular dynamics computer simulations. Nonequilibrium classical trajectory calculations provide insight into the early stages of vibrational energy relaxation of highly excited states. Equilibrium force autocorrelation functions are used to determine the relaxation rate for the $\text{v=1→v=0}$ transition. Good agreement with experiments is found. The calculations suggest that the hydrogen bonding in water, as reflected by the high density of librational modes, is the reason for the fast relaxation in this liquid compared with that in ethanol and acetonitrile.