Decay processes after resonant excitation of S 2p and F 1s electrons in SF6 molecules.

Abstract

S LVV and F KVV resonance Auger spectra have been studied from ${\mathrm{SF}}_{6}$ gas-phase molecules using selective excitation of S 2p and F 1s electrons to different resonance states with high-resolution monochromated synchrotron radiation for S 2p and with lower resolution for F 1s. The normal Auger spectra were measured using both synchrotron radiation and high-energy electron-beam excitation. The kinetic energy shift of the resonance S LVV and F KVV Auger spectra (with a spectator electron in the 6${\mathit{a}}_{1\mathit{g}}$ orbital) relative to the normal Auger spectra are 11.0 and 8.0 eV, respectively. These values, in comparison to the 7.5 eV for the Si LVV Auger shift in ${\mathrm{SiF}}_{4}$, are discussed. The spectator Auger process is the dominating decay channel, but, in the case of S, the participating or autoionization decay channel is also found to be important in enhancing the intensity of bonding levels such as the 4${\mathit{t}}_{1\mathit{u}}$ level in the outer valence band and especially the 4${\mathit{a}}_{1\mathit{g}}$ and 3${\mathit{t}}_{1\mathit{u}}$ inner valence-band levels with significant sulfur character. No significant changes in Auger or valence-band spectra were seen at intense above-edge resonances, such as the ${\mathit{e}}_{\mathit{g}}$ resonance at 196-eV photon energy.