A study of low energy electron attachment to trifluoromethyl sulphur pentafluoride, SF5CF3: atmospheric implications

An investigation of electron attachment to the potent greenhouse gas SF,CF, has been carried out in atmospheric pressure nitrogen and argon buffer gas es at 300 K. The experiments were conducted under nonthermal electron-swarm conditions, using an instrument that combines a drift tube with a quadrupo le mass spectrometer. Electron attachment rate constants, k(a), have been d etermined as a function of mean electron energy (<(<epsilon>)over bar> = 0. 04-1.9 eV). k(a) decreases as <(<epsilon>)over bar> increases. The estimate d thermal electron attachment rate constant is k(th)(SF5CF3) approximate to (7.7 +/- 0.6) x 10(-8) cm(3) molecule(-1) s(-1). The only observed anion p roduct is SF;. Free electron attachment destroys SF,CF,. This places an upp er limit on the atmospheric lifetime of SF,CF, of the order of 1000 years. (Int J Mass Spectrom 206 (2001) i-iv) (C) 2001 Elsevier Science B.V.