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

Abstract An investigation of electron attachment to the potent greenhouse gas SF 5 CF 3 has been carried out in atmospheric pressure nitrogen and argon buffer gases at 300 K. The experiments were conducted under nonthermal electron-swarm conditions, using an instrument that combines a drift tube with a quadrupole mass spectrometer. Electron attachment rate constants, k a , have been determined as a function of mean electron energy (e = 0.04–1.9 eV). k a decreases as e increases. The estimated thermal electron attachment rate constant is k th (SF 5 CF 3 ) ≈ (7.7 ± 0.6) × 10 −8 cm 3 molecule −1 s −1 . The only observed anion product is SF 5 − . Free electron attachment destroys SF 5 CF 3 . This places an upper limit on the atmospheric lifetime of SF 5 CF 3 of the order of 1000 years.