Core-hole screening

Stdhr J and Jaeger R 1982 Adsorption-edge resonances, core-hole screening and orientation of chemisorbed molecules CO, NO and N2 on Ni(IOO) Rhys. Rev. B 26 4111-31... 

Of direct interest for photoemission of supported catalysts is that similar increases in the width of d-bands have been observed by Mason in UPS spectra of small metal particles deposited on amorphous carbon and silica substrates [48]. Theoretical calculations by Baetzold et al. [49] indicate that the bulk density of states is reached if Ag particles contain about 150 atoms, which corresponds to a hemispherical particle 2 nm in diameter. Concomitant with the appearance of narrowed d-bands in small particles is the occurrence of an increase in core level binding energies of up to 1 eV. The effect is mainly an initial and only partly a final state effect [48], although many authors have invoked final state - core hole screening effects as the only reason for the increased binding energy. 

F.P. Larkins, Influence of core hole screening on molecular Auger rates and inner-shell lifetimes, J. Electron Spectrosc. Relat. Phenom. 67 (1994) 159. 

The Al(2p) spectra for aluminum on P30T, as a function of the coverage, are shown in Fig. 7.4. These spectra exhibit two interesting features. First, the main Al(2p) line gradually shifts towards lower binding energy as the thickness of the aluminum layer increases. This is a consequence of the improved core-hole screening for... 

O. Wessely et al., Dynamical core-hole screening in the x-ray absorption spectra of hydrogenated carbon nanotubes and graphene. Phys. Rev. B 76, 161402 (2007)... 

The calculations were performed using the Hedin-Lundquist exchange correlation potential. When X-ray absorption spectra are calculated, a core-hole has to be present in order to mimic the photon absorption process. The calculations were performed both with and without complete core-hole screening. The optimal geometry for the clusters as derived from the ADF calculations was used as input for the FEFF8 calculations. 

Various theoretical models, such as the excited-atom approach [1] and the thermochemical model [2,3] have been proposed for the determination of these shil ts. A model based on the density-functional theory has been suggested and applied for the analysis of core hole screening in simple metals by Ambladh and von Barth [4] and by Williams and Lang [5]. Spin-polarised density-functional... 

Stbhr, 1. and Jaeger, R., Absorption-edge resonances, core-hole screening, and orientation of chemisorbed molecnles Co, No, and N-2 on Ni(lOO), Physical Rev. B 26, 4111 131, 1982. 

In addition to the valence-band photoemission, useful information can be obtained from 4f core-level spectra, because their line shape is almost exclusively influenced by the various types of screening of a 4f hole by conduction-band states. The presence of the 7 eV satellites is taken as an indication for a decreasing hybridization and consequent increasing localization of the 5f states in the uranium compounds (Schneider and Laubschat 1981a). Various aspects of the core-hole screening are discussed by Naegele et al. (1985). 

Fig. I. Low-energy satellite structures (indicated by S) in the region of the 3d XPS spectra of La and Sm metal and of Ce in CeSb, pointing to the need of a dynamical description of the core hole screening mechanism (Wertheim and Campagna 1978).

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