PHOTODISSOCIATION DYNAMICS OF CHF2CL AFTER PHOTOEXCITATION AT THE LYMAN-ALPHA WAVELENGTH (121.6 NM)

The collision-free gas-phase photodissociation dynamics of CHF2Cl (HCF C-22) were studied at room temperature using the laser photolysis/lase r-induced fluorescence ''pump/probe'' technique. Lyman-or laser radiat ion (lambda = 121.6 nm) was used both to photodissociate the parent mo lecule and to detect the nascent H atom products via (2p(2)P <-- 1s(2) S) laser-induced fluorescence. An absolute H atom quantum yield of Phi (H) = 0.77 +/- 0.13 was determined by a calibration method in which H2 O photolysis at 121.6 nm was used as a reference source of well-define d H atom concentrations. The line shapes of the measured H atom Dopple r profiles indicate a bimodal velocity distribution suggesting the pre sence of two different H atom formation pathways in the Lyman-a photod issociation of CHF2Cl.