A full dimensional direct ab initio dynamics study of the electron capture by SF 6

Abstract

The dynamics of electron capture by sulfur hexafluoride (SF 6) have been investigated by means of full dimensional direct ab initio dynamics calculations at the HF/6-311G(d)+sp (a diffuse sp-function is further added to sulfur atom) level. A rigid SF 6 structure and narrow Franck–Condon region for electron capture was assumed in choosing initial conditions for the trajectories. The direct ab initio dynamics calculations for the electron capture processes by SF 6 indicated that the SF − 6 ion formed by the vertical electron attachment to SF 6 decomposes into SF − 5 and F via short-lived complex formation (SF − 6). The lifetime of SF − 6 was distributed from 0.1–0.2 ps, which is quite short as lifetime of the intermediate complex. The dynamics calculations showed that 12% of the total available energy is partitioned into the relative translational mode between SF 5 − and F. The effect of solid phase on the dynamics has been examined by introducing a model bath-relaxation time for energy dispersion. There was a possibility that the SF 6 − anion exists in solid phase. The mechanism of the electron capture by SF 6 in gas phase and in solid phase was discussed on the basis of the results.