NONEXPONENTIAL BEHAVIOR IN THE VIBRATIONAL PREDISSOCIATION DYNAMICS OF I2(B, NU)-AR13

The vibrational predissociation dynamics of an Ar13 cluster containing a vibrationally excited I2 molecule in its B electronic state are studied by classical trajectory simulation. The kinetics of the loss of the first Ar atom from the cluster induced by vibrational relaxation of the diatomic exhibits unusual nonexponential behavior, characterized by an instantaneous rate that increases with time. The simulation results are modeled by a hybrid statistical model, which explicitly takes into account the slow relaxation of the impurity while assuming rapid redistribution of energy among the low frequency cluster modes. Minor deviations between the simulation and theory are observed, and indicate nonstatistical effects in the "solvent" degrees of freedom.