Electron transfer and bond-forming reactions following collisions of SF2+ with Ar

Collisions between SF2+ and Ar have been investigated using time-of-flight mass spectrometry over a collision energy range of 2.6-6.2 eV in the centre-of-mass frame. The formation of SF+, S+ and Ar+ in single electron transfer reactions has been detected and the cross-sections, in arbitrary units, for forming these species have been evaluated. This electron transfer reactivity has been rationalized by Landau-Zener calculations. The reactivity in this collision system also involves an unusual bond-forming reaction which generates ArS2+. Quantum chemical calculations of the relevant energetics show that the lowest lying singlet and triplet states of ArS2+ are bound and are energetically accessible to this collision system at the above collision energies. This energetics analysis also shows that electron transfer in the exit channel between the separating ArS2+ and F atom is likely to be inefficient, explaining why we detect the observed products and not ArS+ + F+.