Transition energies of barium and radium by the relativistic coupled-cluster method

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.53.3050· OSTI ID:283838

Eliav, E; Kaldor, U ^[1]; Ishikawa, Y ^[2]

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1. School of Chemistry, Tel Aviv University, 69978 Tel Aviv (Israel)
2. Department of Chemistry, University of Puerto Rico, P.O. Box 23346, San Juan, Puerto Rico 00931-3346 (United States)

The relativistic coupled-cluster method is used to calculate ionization potentials and excitation energies of the barium and radium atoms and their monocations. Large basis sets are used, with {ital l} up to 5, the Dirac-Fock or Dirac-Fock-Breit orbitals found, and the external 28 electrons of barium or 42 electrons of radium are correlated by the coupled-cluster method with single and double excitations. Good agreement (within a few hundred wave numbers) is obtained for the ionization potentials and low excitation energies (up to 3 eV for Ba, 4 eV for Ra). The Breit interaction has little effect on the excitation energies, but it improves significantly the fine-structure splittings of Ra. Large relativistic effects on the energies are observed, up to 1 eV for barium and 2 eV for radium. The nonrelativistic ground states of Ba{sup +} and Ra{sup +} are ({ital n}{minus}1){ital d} {sup 2}{ital D} rather than {ital ns} {sup 2}{ital S}. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 283838
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 5 Vol. 53; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARIUM IONS
COUPLED MODES
ENERGY-LEVEL TRANSITIONS
EV RANGE 01-10
EXCITATION
FINE STRUCTURE
IONIZATION POTENTIAL
POTENTIALS
RADIUM IONS
RELATIVISTIC RANGE
S STATES