Interference between Extrinsic and Intrinsic Losses in XAFS

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dc.creatorCampbell, L.
dc.creatorHedin, L.
dc.creatorRehr, J. J.
dc.creatorBardyszewski, W.
dc.date2001-10-31
dc.date.accessioned2026-07-07T02:43:20Z
dc.date.available2026-07-07T02:43:20Z
dc.descriptionThe interference between extrinsic and intrinsic losses in x-ray absorption fine structure (XAFS) is treated within a Green's function formalism, without explicit reference to final states. The approach makes use of a quasi-boson representation of excitations and perturbation theory in the interaction potential between electrons and quasi-bosons. These losses lead to an asymmetric broadening of the main quasi-particle peak plus an energy-dependent satellite in the spectral function. The x-ray absorption spectra (XAS) is then given by a convolution of an effective spectral function over a one-electron cross-section. It is shown that extrinsic and intrinsic losses tend to cancel near excitation thresholds, and correspondingly, the strength in the main peak increases. At high energies, the theory crosses-over to the sudden approximation. These results thus explain the observed weakness of multi-electron excitations in XAS. The approach is applied to estimate the many-body corrections to XAFS, beyond the usual mean-free-path, using a phasor summation over the spectral function. The asymmetry of the spectral function gives rise to an additional many-body phase shift in the XAFS formula.
dc.description14 pages, 7 figures (LaTeX-RevTeX4). Submitted to Physical Review B
dc.identifierhttps://arxiv.org/abs/cond-mat/0110643
dc.identifierhttp://arxiv.org/abs/cond-mat/0110643
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/18458
dc.subjectMaterials Science
dc.titleInterference between Extrinsic and Intrinsic Losses in XAFS
dc.typetext

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