Relativistic configuration-interaction calculations of [ital n]=2 triplet states of heliumlike ions

Journal Article · Sat May 01 04:00:00 EDT 1993 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.47.3692· OSTI ID:6649264

Chen, M H; Cheng, K T ^[1]; Johnson, W R ^[2]

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1. University of California, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)
2. Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

Eigenfunctions and eigenvalues of the relativistic no-pair Hamiltonian are determined for [ital n]=2 triplet states of heliumlike ions with charges in the range [ital Z]=5--100. The eigenfunctions are expanded in a basis of two-electron wave functions constructed from Dirac-Coulomb orbitals restricted to a finite cavity. The Hamiltonian matrix is evaluated and Davidson's method is then used to determine the lowest few eigenfunctions and eigenvalues. These calculations, which include the Coulomb interaction and the retarded Breit interaction, are corrected for QED and mass-polarization effects using values from Drake's unified method and are compared with other calculations and with experiment. For low-[ital Z] ions, the present calculations agree well with many-body perturbation theory and with the unified method, but disagree substantially with multiconfiguration Dirac-Fock (MCDF) calculations corrected for correlations. At [ital Z]=36, our term energies are lower than the unified method by [lambda][alpha][sup 4][ital Z4] a.u., where [lambda]=0.033, 0.51, 0.16, and 0.003 for the 2 [sup 3][ital S][sub 1], 2 [sup 3][ital P][sub 0], 2 [sup 3][ital P][sub 1], and 2 [sup 3][ital P][sub 2] states, respectively. For [ital Z]=47 and 64, the present values of the 2 [sup 3][ital P][sub 0--]2 [sup 3][ital P][sub 1] fine structure agree better with MCDF predictions than with the unified method. The energy intervals 2 [sup 3][ital P][sub 0][minus]2 [sup 3][ital S][sub 1], 2 [sup 3][ital P][sub 1][minus]2 [sup 3][ital S][sub 1], 2 [sup 3][ital P][sub 2][minus]2 [sup 3][ital S][sub 1], and 2 [sup 3][ital P][sub 0][minus]2 [sup 3][ital P][sub 1] are consistent with experiment throughout the entire range of [ital Z].

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6649264
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 47:5; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664100* -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
CHARGED PARTICLES
CONFIGURATION INTERACTION
EIGENFUNCTIONS
EIGENVALUES
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY RANGE
FLUIDS
FUNCTIONS
GASES
HELIUM
IONS
ISOELECTRONIC ATOMS
MANY-BODY PROBLEM
MULTICHARGED IONS
MULTIPLETS
NONMETALS
RARE GASES
RELATIVISTIC RANGE
TRIPLETS
TWO-BODY PROBLEM