Implementation of laser induced fluorescence technique to study the kinetics of radicals generated in the IR multiphoton dissociation of chloroform

Abstract

In this work we present the design and implementation of an experimental facility for the study of the reaction mechanisms of the CCl2 radicals produced in the Infrared Multiple-Photon Dissociation of CDCl3. The design of this facility was performed by combining two techniques: Laser Induced Fluorescence (LIF) and Infrared Multiple-Photon Dissociation (IRMPD). A TEA CO2 laser and a dye laser were synchronized to couple both techniques. The IRMPD of CDCl3 with a TEA CO2 laser produces CCl2 radicals and DCl as main products. The dye laser was used for the electronic excitation of the CCl2 radicals. The relaxation of these radicals to the ground level gives rise to the fluorescence signal which is proportional to the radicals' concentration. The kinetics of the CCl2 radicals was studied by analyzing the fluorescence signal intensity for different delay times between both lasers radiation. We also present the data acquisition system developed, the kinetic model proposed to explain the experimental results and the rate constants values kO2 and kHCl determined for the reactions of the CCl2 radicals with O2 and HCl.