Normal and resonanceLVVAuger spectra of gas-phaseSiCl4molecules

Abstract

Si LVV and Cl LVV Auger spectra of ${\mathrm{SiCl}}_4$ have been studied in the gas phase with the use of different photon energies from synchrotron radiation or an electron beam, either to ionize 2p electrons or to excite them selectively to unfilled molecular or Rydberg orbitals. In the case of resonance excitation, the kinetic energies of the main Auger peaks have been found to depend clearly on the antibonding molecular orbital to which the 2p electrons have been excited. For the excitation at the first strong resonance maximum, the Si LVV kinetic energies have been found to be 5.2 eV higher than the energies of the corresponding peaks in the normal Auger spectrum. This shift compares with 7.5 eV for the equivalent excitation in ${\mathrm{SiF}}_4$. In the case of Cl, the spectator Auger spectra show very high intensity and broad structureless peaks. Valence-band intensities do not vary greatly at either the Si 2p or Cl 2p edges, showing that the spectator Auger process is the major decay mechanism for the resonantly excited core hole.