Accurate local density photoionization cross sections byLCAO Stieltjes imaging approach

Autor: Mauro Stener, Pietro Decleva, Adriana Lisini
Rok vydání: 1995
Předmět:
Zdroj: International Journal of Quantum Chemistry. 53:229-244
ISSN: 1097-461X
0020-7608
DOI: 10.1002/qua.560530208
Popis: Photoionization cross sections are evaluated at the local density level avoiding any potential shape approximation by employing the Stieltjes imaging (ST) technique in conjunction with large (STO ) basis LCAO calculations. The ST technique proves accurate in comparison with full continuum calculation on the noble gases ionization. Several choices for the final-state potentials, including different exchange-correlation potentials, are tested on the noble gases, as well as in H{sub 2}O and CO. Finally, several molecules are investigated employing the transition-state X{alpha} potential and the results compared with available experimental data and previous calculations. The accuracy of the proposed approach appears quite comparable to the ab initio static-exchange level, removing spurious resonances associated to the muffin-tin approximation, and should prove useful in the analysis and interpretation of cross-section data for large systems, where it is shown that basis-set requirements become less stringent. The accuracy obtainable for the cross-section profiles allows close comparison with experimental data, which, although showing good general agreement for the shape of the cross-section profile, indicates the need of a further refinement of the theoretical model. 55 refs., 15 figs., 1 tab.
Databáze: OpenAIRE
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