Experimental and theoretical binding energy spectra and momentum distributions for the valence orbitals of H2O

Abstract

The binding energy spectra (10-46 eV) and momentum distributions of the valence orbitals of H2O have been measured using a new high-sensitivity binary (e,2e) electron spectrometer employing position-sensitive detectors. The binding energy spectrum shows a previously unreported feature at = 27 eV which is shown to be associated with the (2a1)-1 ionization process. The region between 25 and 46 eV is compared with previous (e,2e) and X-ray photoelectron measurements as well as with several existing and new many-body calculations indicating a splitting of the 2a1 ionization pole strength. In addition the separate momentum distributions of the three outer valence orbitals of H2O have been obtained from deconvoluted binding energy spectra run at a series of azimuthal angles. The results, which show considerably improved signal-to-noise ratio over earlier measurements using single-channel instrumentation are compared with spherically averaged momentum distributions calculated with a variety of wavefunctions. Show more