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J C Woicik

Publications and source records attributed to J C Woicik.

5 recordsLinked to original sources
PubMed2002

Hybridization and bond-orbital components in site-specific X-ray photoelectron spectra of rutile TiO2.

We have determined the Ti and O components of the rutile TiO2 valence band using the method of site-specific x-ray photoelectron spectroscopy. Comparisons with calculations based on pseudopotentials within the local density approximation reveal the hybridization of the Ti 3d, 4s, and 4p states, and the O 2s and 2p states on each site. These chemical effects are observed due to the large differences between the angular-momentum dependent matrix elements of the photoelectron process.

Journal Article↗
PubMed2000

Direct measurement of valence-charge asymmetry by x-ray standing waves.

By monitoring valence-photoelectron emission under condition of strong x-ray Bragg reflection, we have determined that a majority of GaAs valence charge resides on the anion sites of this heteropolar crystal, in quantitative agreement with the GaAs bond polarity as calculated from the Hartree-Fock term values. In contrast, the valence-charge distribution in Ge is found to be symmetric. In both cases, the valence emission is found to be closely coupled to the atomic cores.

Journal Article↗