Electron impact ionization of CHF3

Electron impact production of ions from CHF, has been studied by a crossed electron beam-molecular beam geometry under single collision conditions for electron incident energies ranging from threshold of ionization to 1000 eV. Ions of CF3+ CHF2+, CF2+, CHF+, CF+, F+, CH+, and C+ are observed. Cross sections for their production have been measured by utilising the relative flow technique. At each impact energy, the cross sections for the production of individual ions have been summed up in order to yield total cross sections for the generation of all ions. These total cross sections are in good agreement with recent theoretical results of Kim [Proceedings of the 20th International Conference on the Physics of Electronic and Atomic Collisions, Vienna, Austria, July 1997, Vol. 1, p. WE 103] and experimental results of Jiao et al. [Chem. Phys. Lett. 269 (1997) 117] in the energy range where the comparison is made. However, there is a considerable disagreement between present results and previously published data and the recommended values of NIST. In addition, appearance energies for each ion have been measured and compared with previously published values. (C) 2001 Elsevier Science B.V.