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Calculation of excitation and photoionization spectra by quasi‐degenerate perturbation theory
Author(s) -
Lisini Adriana,
Decleva Piero
Publication year - 1994
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560520224
Subject(s) - photoionization , degenerate energy levels , excitation , spectral line , atomic physics , valence (chemistry) , perturbation (astronomy) , chemistry , wave function , perturbation theory (quantum mechanics) , basis set , x ray photoelectron spectroscopy , configuration interaction , physics , excited state , ionization , quantum mechanics , computational chemistry , density functional theory , ion , nuclear magnetic resonance
The ability of the QDPT CI method, in which the quasi‐degenerate perturbation theory is applied within the configuration interaction ( CI ) approach, in dealing with the calculation of excitation and photoionization spectra is shown through an overview of comparisons between the QDPT CI values and the full CI ones in the same basis set. A direct comparison with the experimental data is given for the core photoelectron spectrum of Ne and the valence photoelectron spectra of Ar and HCl. The quality of the results obtained is very satisfactory, both as regards the energies and the wave functions, indicating the validity and the flexibility of the method that can confidently be applied also in cases where strong correlation effects are present. © 1994 John Wiley & Sons, Inc.