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THE COMPLETE VALENCE SHELL PHOTOELECTRON-SPECTRA OF CH3F, CH3CL, AND CH3BR USING SYNCHROTRON-RADIATION AT H-NU=72 EV - A COMPARISON WITH MANY-BODY GREENS-FUNCTION CALCULATIONS

TitleTHE COMPLETE VALENCE SHELL PHOTOELECTRON-SPECTRA OF CH3F, CH3CL, AND CH3BR USING SYNCHROTRON-RADIATION AT H-NU=72 EV - A COMPARISON WITH MANY-BODY GREENS-FUNCTION CALCULATIONS
Publication TypeJournal Article
Year of Publication1993
AuthorsOlney, TN, Chan, WF, Cooper, G, Brion, CE, Tan, KH
JournalJOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA
Volume66
Pagination83-100
Date PublishedDEC 20
ISSN0368-2048
Abstract

The valence shelf binding energy spectra of CH3F, CH3Cl, and CH3Br have been measured in both the outer and inner valence regions using monochromated synchrotron radiation at a photon energy of 72 eV. The spectrum of CH3Br was also recorded at photon energies of 68 and 70 eV in order to avoid the resonance Auger processes from Br3d excitation which occur in addition to direct ionization in CH3Br at 72 eV. In the inner Valence region the spectra exhibit several peaks and broad structures indicating a breakdown of the independent particle picture due to the role of electron correlation effects in the photoionization process. The spectra are compared with previously published many-body Green's function calculations, and with binding energy spectra from electron momentum spectroscopy, in order to assign the photoelectron bands and pole strength distributions in the inner valence regions. The photoelectron spectrum of CH3Br at 72 eV shows clear evidence of resonance Anger processes in which the Br3d –> sigma{*} excited electron acts as a spectator in the electronic decay. Evidence for participator autoionization processes is also observed. The spectrum also shows weak but sharp peaks, some of which are at energies corresponding to autoionization of 3d excited Br atoms formed from the rapid dissociation of excited CH3Br in accord with the earlier suggestions of Nenner et al. (J. Electron Spectrosc. Relat. Phenom., 52 (1990) 623).

DOI10.1016/0368-2048(93)01832-Y