C-Cl and C-H bond cleavage in 193 nm photodissociation of CH₃CF₂Cl and CH₃CFCl₂

The relative amounts of Cl(²P_3/2) [Cl], Cl(²P,_1/2) [Cl*], H, and HCl produced by 193 nm photodissociation of CH₃CF₂Cl and CH₃CFCl₂ were studied by a laser pump-and-probe technique. An excimer laser photodissociated the parent molecules and a frequency doubled tunable dye laser probed the photofragments via ( 2 + 1 ) resonantly enhanced multiphoton ionization coupled with a time-of-flight mass spectrometer. Only atomic products were observed; no HCl was found. The profiles were well fitted to Gaussians. The Cl*/Cl branching ratios were almost identical, 0.18 ±0.04 and 0.16±0.04, while the H/(Cl+Cl*) ratios were 0.67±0.21 and 0.18±0.07, for CH₃CF₂Cl and CH₃CFCl₂, respectively. The mechanism for the production of the atomic species is discussed.