Thermal lensing study on the kinetics of IR multiphoton dissociation

Abstract

Thermal lensing (TL) signals from CCIF ₂ CHCl ₂ gas undergoing IR multiphoton dissociation (IRMPD) have been observed. The rising rate of the TL signals increases with increasing laser energy fluence above the reaction threshold fluence, while it is constant below the threshold fluence. An explanation is given by comparing the result with a kinetic model, in which the rate of the vibrational deactivation of both the reactant and product molecules and a unimolecular reaction rate of the vibrationally excited molecules are taken into account. The applicability of the TL method to investigations of the IRMPD is mentioned.