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EOM /Propagator ionization potentials: Effect of an extended operator manifold on the predicted valence‐shell ionization spectra of ethane, ethylene, and acetylene
Author(s) -
Baker Jon
Publication year - 1985
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.560270205
Subject(s) - valence (chemistry) , acetylene , propagator , ionization , spectral line , chemistry , open shell , atomic physics , physics , ion , quantum mechanics , organic chemistry
The orthogonalized direct diagonalization ( ODD ) method is used to predict the valence‐shell ionization spectra for the series of hydrocarbons ethane (C 2 H 6 ), ethylene (C 2 H 4 ), and acetylene (C 2 H 2 ) within an EOM /propagator formalism. Both (a) third‐order and (b) higher‐order (with h 5 terms in the excitation operator manifold) calculations are presented in order to illustrate the effect of the extended operator manifold on the predicted valence‐shell spectra. It is shown that the major effect of the h 5 manifold is concentrated in its “occupied” part. Along with a general shifting of the main lines for outer valence ionizations to lower values (together with a slight reduction in pole strength), it is found that the effect of the h 5 manifold in the inner valence region is dependent on the system being studied.