Intramolecular vibrational redistribution and energy relaxation in solution: A molecular dynamics approach

Abstract

Recent IR-pump/UV-probe investigations on the intramolecular and intermolecular vibrational energy flow for CH₂I₂ dissolved in CDCl₃ are complemented by classical molecular dynamics simulations. Direct nonequilibrium molecular dynamics simulation is able to reproduce significant features of the energy gain and loss in Franck–Condon-active CI₂ stretch modes as observed via the UV-probe pulse. A key finding of our simulations is the fact that most of the excess energy deposited by the IR-pump pulse is dissipated into the solvent via the CH-mode of lowest frequency (CH₂ rocking vibration) while the mode of lowest frequency (CI₂ bending) is merely a spectator in the overall process of energy redistribution and relaxation.