Ion and electron impact ionisation of CF 4 studied via uv emission

Abstract

UV emission spectra produced by 1–25 keV He +, Ne +, H + ion and 0−1 keV electron impact on CF 4 were obtained and solute emission cross sections of bands determined. The energy dependence of the ion impact data is qualitatively in accord with the Rapp-Francis theory of charge transfer and yields ionisation energies of CF 4 via the Massey criterion. The electron data are discussed in terms of the Bethe theory and are related to the ion impact results and photoionisation data. Elimination of energetically inaccessible fragmentation pathways for the CF 4 +(C̃, D̃) ions indicates that the possible emitters are CF 3 + and CF 4 +.