Vacuum UV spectroscopy and dynamics of CF3Cl, CF2Cl2 and CFCl3: analysis of emissions and evidence for parent ion emission from CF3Cl

Fluorescence processes following electron impact, He* and Ne* rare-gas metastable impact, and tunable vacuum UV photon excitation of CF 3 Cl, CF 2 Cl 2 and CFCl 3 are observed. Using the first two techniques, emission spectra are dominated by CF 2 Ã-[Xtilde] fluorescence. Using photons in the energy range 11-35eV, four different decay channels are observed: (1) with CF 3 Cl, CF 3 fluorescence for photon energies 11-13eV; (2) with CF 3 Cl and CF 2 Cl 2 , CF 2 fluorescence for energies 13-18 eV, (3) with CF 2 Cl 2 , CF fluorescence for energies 18-22 eV; (4) with CF 3 Cl, parent ion emission for energies greater than 20 eV. No fluorescence of comparable intensity is observed from CFCl 3 with photon excitation in this range. The emitting electronic state in CF 3 Cl + is the Ẽ 2 A 1 state with a vertical ionisation potential of 20·2 eV and a radiative lifetime of 25 ns.