CL (2PJ) FINE-STRUCTURE QUANTUM YIELDS FROM UV DISSOCIATION OF PCL3, CCL4, CHCL3 AND CL2 IN A SUPERSONIC JET

Jet-cooled phosphorus trichloride, carbon tetrachloride, chloroform and molecular chlorine are photodissociated in the UV wavelength range 235-238 nm. Chlorine atom photofragments Cl (P-2(3/2)) and Cl* (P-2(1/2)) are detected via resonance-enhanced (2 + 1) ionization throughout the 232-238 nm wavelength region. The relative Cl* yields, phi* = [Cl*]/([Cl] + [Cl*]), are measured for both Cl-35 and Cl-37 isotopes using the two-photon atomic transitions at 235.3 nm for Cl and 237.8 nm for Cl*. Preliminary results indicate that the Cl* yields are different for the two isotopes for some of the precursors. In addition, we obtained the two-photon oscillator strength of the Cl transition at 237.7 nm relative to the Cl* transition at 237.8 nm. The advantage of using the two-photon Cl transition at 237.7 nm for quantum yield measurements is discussed.