Low-energy electron attachment to SF6 molecules:: Vibrational structure in the cross-section for SF5- formation up to 1 eV

In high resolution electron attachment to SF6, cusp structure due to interchannel coupling has been observed in the cross-section for SF5- formation at the thresholds for vibrational excitation of the SF6(upsilon(1)) mode up to upsilon(1) = 10. It is superimposed on the broad band peaking around 0.55 eV which has been previously attributed to attachment into a repulsive potential surface and subsequent direct dissociation. The newly observed vibrational structure as well as electron energy loss spectra (which exhibit strong excitation of the v, mode up to high quantum numbers) indicate, however, that both the channel yielding the long-lived SF6- anions and the dissociative SF5- + F channel have a common primary attachment process, mediated by the same SF6 scattering state and strongly coupled to the process of vibrational excitation. (c) 2005 Elsevier B.V. All rights reserved.