OVERTONE-INDUCED UNIMOLECULAR DECOMPOSITION OF POLYATOMIC-MOLECULES IN RARE-GAS CLUSTERS - A CLASSICAL TRAJECTORY STUDY OF H2O2-AR13

The effects of intermolecular interactions on the dynamics of intramolecular energy transfer and unimolecular dissociation are studied by considering the overtone-induced unimolecular decomposition of a polyatomic molecule embedded in a rare gas cluster. The system studied is H2O2-Ar13. Classical trajectory calculations are performed on both the isolated molecule and the molecule-cluster complex. The rates and mechanisms of intramolecular energy transfer and molecular decomposition of the complex are investigated and compared with the behavior of isolated H2O2. Three main mechanisms leading to pronounced differences in the intramolecular dynamics and unimolecular decay rates are identified: vibrational deactivation of the excited molecule, modification of intramolecular vibrational energy redistribution (IVR) pathways by molecule-cluster interactions, and recombination of the nascent OH fragments induced by binding to the cluster and subsequent diffusion on its surface.