skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: CI+MBPT calculations of Ar I energies, g factors, and transition line strengths

Abstract

Excited states of noble gas atoms present certain challenges to atomic theory for several reasons: first, relativistic effects are important and LS coupling is not optimal; second, energy intervals can be quite small, leading to strong mixing of states; third, many-body perturbation theory for hole states does not converge well. Previously, some attempts were made to solve this problem, using for example the all-order coupled-cluster approach and particle-hole configuration-interaction many-body perturbation theory (CI-MBPT) with modified denominators. However, while these approaches were promising, the accuracy was still limited. In this study, we calculate Ar I energies, g factors, and transition amplitudes using ab initio CI-MBPT with eight valence electrons to avoid the problem of slow convergence of MBPT due to strong interaction between 3p and 3s states. We also included in CI many dominant states obtained by double excitations of the ground state configuration. Thus perturbation corrections were needed only for 1s, 2s, 2p core electrons non-included in valence-valence CI, which are quite small. We found that energy, g factors, and electric dipole matrix elements are in reasonable agreement with experiments. It is noteworthy that the theory agreed well with accurately measured g factors. Finally, experimental oscillator strengths have large uncertainty,more » so in some cases we made a comparison with average values.« less

Authors:
ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1475359
Report Number(s):
LA-UR-18-20021
Journal ID: ISSN 0953-4075
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physics. B, Atomic, Molecular and Optical Physics
Additional Journal Information:
Journal Volume: 51; Journal Issue: 6; Journal ID: ISSN 0953-4075
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; Ar I; oscillator strengths; g-factors; CI-MBPT; energy levels

Citation Formats

Savukov, I. M. CI+MBPT calculations of Ar I energies, g factors, and transition line strengths. United States: N. p., 2018. Web. doi:10.1088/1361-6455/aaac0d.
Savukov, I. M. CI+MBPT calculations of Ar I energies, g factors, and transition line strengths. United States. doi:10.1088/1361-6455/aaac0d.
Savukov, I. M. Wed . "CI+MBPT calculations of Ar I energies, g factors, and transition line strengths". United States. doi:10.1088/1361-6455/aaac0d. https://www.osti.gov/servlets/purl/1475359.
@article{osti_1475359,
title = {CI+MBPT calculations of Ar I energies, g factors, and transition line strengths},
author = {Savukov, I. M.},
abstractNote = {Excited states of noble gas atoms present certain challenges to atomic theory for several reasons: first, relativistic effects are important and LS coupling is not optimal; second, energy intervals can be quite small, leading to strong mixing of states; third, many-body perturbation theory for hole states does not converge well. Previously, some attempts were made to solve this problem, using for example the all-order coupled-cluster approach and particle-hole configuration-interaction many-body perturbation theory (CI-MBPT) with modified denominators. However, while these approaches were promising, the accuracy was still limited. In this study, we calculate Ar I energies, g factors, and transition amplitudes using ab initio CI-MBPT with eight valence electrons to avoid the problem of slow convergence of MBPT due to strong interaction between 3p and 3s states. We also included in CI many dominant states obtained by double excitations of the ground state configuration. Thus perturbation corrections were needed only for 1s, 2s, 2p core electrons non-included in valence-valence CI, which are quite small. We found that energy, g factors, and electric dipole matrix elements are in reasonable agreement with experiments. It is noteworthy that the theory agreed well with accurately measured g factors. Finally, experimental oscillator strengths have large uncertainty, so in some cases we made a comparison with average values.},
doi = {10.1088/1361-6455/aaac0d},
journal = {Journal of Physics. B, Atomic, Molecular and Optical Physics},
number = 6,
volume = 51,
place = {United States},
year = {2018},
month = {1}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share: