Infrared Multiphoton Dissociation of CF₃CHClF: Primary Dissociation and Secondary Photolysis

Abstract

The dissociation yield and branching ratio in CO2 laser-induced infrared multiphoton dissociation (IRMPD) of CF3CHClF were investigated by irradiation at 9R(20) 1078.6 cm−1 under an unfocused irradiation geometry (0.75-2.3 J/cm2) and a mildly focused one (1.2-18 J/cm2). By using a Br2-scavenging technique, it was revealed that the primary dissociation of CF3CHClF proceeded mainly via three-centered HCl molecular elimination and C-Cl bond rupture, with minor contributions of C-C bond rupture and HF molecular elimination at higher fluences. The secondary photolysis of the primarily produced species during the laser pulse to yield CF2 and CClF carbenes depended strongly upon the laser fluence.