Infrared Multiphoton Dissociation Mechanism of 1,2-Dichlorotrifluoroethane in a Molecular Beam

Abstract

Abstract The mechanism of the infrared multiphoton dissociation of the title molecule has been studied using photofragmentation translational spectroscopy. The HCl elimination and the C–Cl bond rupture occurred competitively as primary dissociation channels. The HCl elimination reaction accounts for % of the total primary dissociation yields at 16 ± 3 J cm−2. This is consistent with the branching ratio calculated by RRKM theory. A C=C bond rupture of the CF2CFCl molecules and C–Cl bond rupture of C2HF3Cl radicals were also observed as secondary photodissociation processes. The average excitation energy of the dissociating 1,2-dichlorotrifluoroethane molecules was found to be 14—36 kcal mol−1 (1 kcal mol−1 = 4.184 kJ mol−1) above the C–Cl dissociation threshold of the molecules by comparing the observed center-of-mass translational energy distribution for the C–Cl bond rupture with that calculated by Rice–Ramsperger–Kassel–Marcus (RRKM) theory.