dorsal/arxiv
View SchemaThird-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences
| Authors | H. C. Ho, W. R. Johnson, S. A. Blundell, M. S. Safronova |
|---|---|
| Categories | |
| ArXiv ID | physics/0606205 |
| URL | https://arxiv.org/abs/physics/0606205 |
| DOI | 10.1103/PhysRevA.74.022510 |
Abstract
Relativistic third-order MBPT is applied to obtain energies of ions with two valence electrons in the no virtual-pair approximation (NVPA). A total of 302 third-order Goldstone diagrams are organized into 12 one-body and 23 two-body terms. Only third-order two-body terms and diagrams are presented here, owing to the fact that the one-body terms are identical to the previously studied third-order terms in monovalent ions. Dominant classes of diagrams are identified. The model potential is a Dirac-Hartree-Fock $V^{N-2}$ potential, and B-spline basis functions in a cavity of finite radius are employed in the numerical calculations. The Breit interaction is taken into account through second order of perturbation theory and the lowest-order Lamb shift is also evaluated. Sample calculations are performed for berylliumlike ions with Z = 4--7, and for the magnesiumlike ion P IV. The third-order energies are in excellent agreement with measurement with an accuracy at 0.2% level for the cases considered. Comparisons are made with previous second-order MBPT results and with other calculations. The third-order energy correction is shown to be significant, improving second-order correlation energies by an order of magnitude.
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"abstract": "Relativistic third-order MBPT is applied to obtain energies of ions with two\nvalence electrons in the no virtual-pair approximation (NVPA). A total of 302\nthird-order Goldstone diagrams are organized into 12 one-body and 23 two-body\nterms. Only third-order two-body terms and diagrams are presented here, owing\nto the fact that the one-body terms are identical to the previously studied\nthird-order terms in monovalent ions. Dominant classes of diagrams are\nidentified. The model potential is a Dirac-Hartree-Fock $V^{N-2}$ potential,\nand B-spline basis functions in a cavity of finite radius are employed in the\nnumerical calculations. The Breit interaction is taken into account through\nsecond order of perturbation theory and the lowest-order Lamb shift is also\nevaluated. Sample calculations are performed for berylliumlike ions with Z =\n4--7, and for the magnesiumlike ion P IV. The third-order energies are in\nexcellent agreement with measurement with an accuracy at 0.2% level for the\ncases considered. Comparisons are made with previous second-order MBPT results\nand with other calculations. The third-order energy correction is shown to be\nsignificant, improving second-order correlation energies by an order of\nmagnitude.",
"arxiv_id": "physics/0606205",
"authors": [
"H. C. Ho",
"W. R. Johnson",
"S. A. Blundell",
"M. S. Safronova"
],
"categories": [
"physics.atom-ph"
],
"doi": "10.1103/PhysRevA.74.022510",
"title": "Third-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences",
"url": "https://arxiv.org/abs/physics/0606205"
},
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