Electron Attachment to and Anion Reactions with SF₅Cl: electron-swarm and Selected Ion Flow Tube studies

The first investigation of non-thermal electron attachment to SF5Cl in a swarm environment is reported here. An electron swarm mass spectrometer. the drift tube of which operates in an atmospheric pressure of N-2 or Ar, has been used to obtain the data. Experimental attachment rate coefficients. k(a). and the anion products resulting from electron attachment are reported. k(a) is observed to decrease as the mean electron energy increases. The estimated thermal (300 K) electron attachment rate constant is k(th) approximate to (1.3 +/- 0.4) x 10(-8) cm(3) s(-1), which is significantly less than the expected s-wave capture rate. The mass spectra obtained show a number of anions resulting from electron attachment, namely F-2(-). SF4-. SF5- and SF5Cl-, with SF5- and SF5Cl- being the only anions observed as the mean electron energy approaches zero. Anion reactions with SF5Cl made it difficult to accurately assign branching ratios, and therefore only a qualitative description of the results will be presented here. Anion reactions with SF5Cl are of general interest and make interesting comparisons with anion reactions involving SF6. In this paper. we also present the results of a selected ion flow tube study investigating the 300 K reactions of SF5Cl with a number of anions; O-2(-). SF6-. OH-. CF3-. F-. Cl- and SF5-. (C) 2004 Published by Elsevier B.V.