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Use of effective core potentials in perturbation corrections to the Koopmans theorem: Vertical ionization potentials of Cl 2 , ClN 3 , and ClNCO
Author(s) -
Langhoff Stephen R.,
Jaffe Richard L.,
Chong Delano P.
Publication year - 1983
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.560230311
Subject(s) - ionization , ionization energy , perturbation (astronomy) , valence (chemistry) , atomic physics , valence electron , spectral line , chemistry , core electron , physics , perturbation theory (quantum mechanics) , electron , ion , quantum mechanics
The valence‐shell vertical ionization potentials of Cl 2 were calculated by perturbation corrections to the Koopmans theorem using a traditional effective core potential based on a Phillips–Kleinman derivation and an improved effective core potential obtained by Christiansen, Lee, and Pitzer. Comparison of the results with an all‐electron calculation demonstrated the reliability of the Christiansen–Lee–Pitzer effective core potential, which was then used to compute the vertical ionization potentials of ClN 3 and ClNCO. The results shed new light in the interpretation of the photoelectron spectra of these molecules.