Quantum mechanical first Born binary encounter theory of electron impact ionization. II Electron Compton scattering

The first Born binary encounter theory of electron Compton scattering is developed. The theory includes the relationship between the usual x-ray Compton profile and its electron scattering counterpart including corrections for scattering from pairs of target electrons (a correction also necessary in...

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Veröffentlicht in:The Journal of chemical physics 1973, Vol.59 (9), p.4691-4704
Hauptverfasser: Bonham, R. A., Tavard, C.
Format: Artikel
Sprache:eng
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Zusammenfassung:The first Born binary encounter theory of electron Compton scattering is developed. The theory includes the relationship between the usual x-ray Compton profile and its electron scattering counterpart including corrections for scattering from pairs of target electrons (a correction also necessary in the x-ray case at small scattering angles) and for exchange and interference scattering. In addition correction terms are derived for the difference between the complete first Born treatment and the binary encounter model. The corrections in the angular range of 10°–60° at an incident electron energy of 25 keV are shown to be negligible. The target electron pair corrections at an incident electron energy of 25 keV are important only for small angle scattering for the lighter elements (< 7° for He) but may extend to larger angles for the heavier elements (< 30° for Ar). Exchange and interference between exchange and direct scattering become significant at the 1% accuracy level at a scattering angle of 4° at the same incident energy. Between 4° and 45° interference between the exchange and direct amplitude dominates the correction term which can amount to 25% of the direct scattering contribution at 35° although it largely vanishes at 45°. Beyond 45° the pure exchange terms rapidly dominate the scattering with increasing angle, and relativistic corrections become increasingly important. In this region the theory can break down and it is suggested that accurate experimental data could be helpful in arriving at a detailed description of the exchange process. A definition for an electron Compton profile including exchange and interference corrections from which the one-electron target momentum density can be extracted is suggested. The theory is also compared with recent experimental work for the case of He, and predictions for the scattered electron intensity as a function of energy loss and scattering angle are made for He at an incident electron energy of 25 keV.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.1680682