Intramolecular vibrational redistribution and fragmentation dynamics of I2 ⋯ Nen (n=2–6) clusters

Abstract

Intramolecular vibrational energy redistribution and fragmentation dynamics in I2(B,v=22) ⋯ Nen (n=2–6) and I2(B,v=21) ⋯ Nen (n=2–5) clusters is studied by hybrid quantum/classical techniques and the results are compared with experiments. A vibrational version of the molecular dynamics with quantum transitions (MDQT) treatment is used in which the vibrational degree of freedom of I2 is treated quantum mechanically while all the other degrees of freedom are treated classically. The potential energy surface is represented as a sum of pairwise interactions with parameters taken from the literature. The calculated product state distributions are in very good agreement with the experiments. Fragmentation lifetimes were also calculated and agree reasonably well with those measured in time-dependent experiments. Fragmentation proceeds via sequential ejection of Ne monomers through three different mechanisms: (i) sequential intramolecular vibrational redistribution plus vibrational predissociation (in which the I2 molecule loses more than one quantum of vibration); (ii) direct vibrational predissociation (in which the I2 molecule loses only one quantum of vibration); (iii) evaporation (in which the I2 molecule remains in the same vibrational state).