Vacuum UV spectroscopy and dynamics of CF3Cl, CF2Cl2and 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 CF3Cl, CF2Cl2 and CFCl3 are observed. Using the first two techniques, emission spectra are dominated by CF2 Ã-[Xtilde] fluorescence. Using photons in the energy range 11–35eV, four different decay channels are observed: (1) with CF3Cl, CF3 fluorescence for photon energies 11–13eV; (2) with CF3Cl and CF2Cl2, CF2 fluorescence for energies 13–18 eV, (3) with CF2Cl2, CF fluorescence for energies 18–22 eV; (4) with CF3Cl, parent ion emission for energies greater than 20 eV. No fluorescence of comparable intensity is observed from CFCl3 with photon excitation in this range. The emitting electronic state in CF3Cl+ is the [Etilde]2A1 state with a vertical ionisation potential of 20·2 eV and a radiative lifetime of 25 ns.