Quantum yield of Cl^∗ (²P_½) production in the gas phase photolysis of CCl₄ in the ultraviolet

Abstract

In this paper, we have probed the dynamics of chlorine atom production from the gas phase photodissociation of carbon tetrachloride at 222 and 235 nm. The quantum yield, φ^∗ of Cl^∗ (²P_½) production has been determined by probing the nascent concentrations of both excited (²P_½) and ground state (²P3/2) chlorine atoms by suitable resonance-enhanced multiphoton ionization (REMPI) detection schemes. Although at the photolysis wavelengths the absorption of carbon tetrachloride is weak, significant amounts of Cl^∗ are produced. Surprisingly, the quantum yield of Cl^∗ production does not follow the absorption spectrum closely, which gives rise to the possibility of an indirect dissociation mechanism present in CCl₄ along with direct dissociation at these ultraviolet wavelengths.