Many-body calculation of photoionization cross sections in CO

Journal Article · Tue Feb 01 04:00:00 EST 1994 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.49.939· OSTI ID:5224272

Veseth, L ^[1]

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1. Department of Physics, University of Oslo, 0316 Oslo (Norway)

Total and partial photoionization cross sections are computed for CO at the fixed equilibrium internuclear separation. Finite basis sets were used, with no explicit recourse to continuum orbitals, and there is no need for input of empirical data such as the ionization threshold. By the present method the first step is to compute the (real) polarizability [alpha]([ital i][eta]) on the imaginary frequency axis. Many-body perturbation theory is used for that purpose, and the expansion is complete to second order in the Coulomb interaction. In the next step the cross sections are obtained from [alpha]([ital i][eta]) by inverting a simple integral equation of the Fredholm first kind (dispersion relation). For the partial cross sections, extra approximations may be necessary, as some diagrams to first and second order make contributions to more than one specific partial cross section. The computed total cross section is in very good agreement with experiment, and good agreement is also obtained for the 1[pi] partial cross section. For the strongly interacting [sigma] shells, the comparison with experiment is less certain. The present results, which include comprehensive correlation corrections, are also compared with existing theoretical results that are on the independent-particle level of accuracy.

• OSTI ID: 5224272
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 49:2; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DISTANCE
ELECTRICAL PROPERTIES
EQUATIONS
INTEGRAL EQUATIONS
INTERATOMIC DISTANCES
IONIZATION
MANY-BODY PROBLEM
OXIDES
OXYGEN COMPOUNDS
PERTURBATION THEORY
PHOTOIONIZATION
PHYSICAL PROPERTIES
POLARIZABILITY