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Title: Theoretical spectroscopy study of the low-lying electronic states of UX and UX{sup +}, X = F and Cl

Abstract

Spectroscopic constants (T{sub e}, r{sub e}, B{sub 0}, ω{sub e}, and ω{sub e}x{sub e}) have been calculated for the low-lying electronic states of UF, UF{sup +}, UCl, and UCl{sup +} using complete active space 2nd-order perturbation theory (CASPT2), with a series of correlation consistent basis sets. The latter included those based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess Hamiltonians for the U atom. Spin orbit (SO) effects were included a posteriori using the state interacting method using both PP and Breit Pauli (BP) operators, as well as from exact two-component methods for U{sup +} and UF{sup +}. Complete basis set (CBS) limits were obtained by extrapolation where possible and the PP and BP calculations were compared at their respective CBS limits. The PP-based method was shown to be reliable in calculating spectroscopic constants, in particular when using the state interacting method with CASPT2 energies (SO-CASPT2). The two component calculations were limited by computational resources and could not include electron correlation from the nominally closed shell 6s and 6p orbitals of U. UF and UCl were both calculated to have Ω = 9/2 ground states. The first excited state of UCl was calculated to be an Ω = 7/2 state atmore » 78 cm{sup −1} as opposed to the same state at 435 cm{sup −1} in UF, and the other low-lying states of UCl showed a similar compression relative to UF. Likewise, UF{sup +} and UCl{sup +} both have Ω = 4 ground states and the manifold of low-lying excited Ω = 3, 2, 1, 0 states was energetically closer together in UCl{sup +} than in UF{sup +}, ranging up to 776 cm{sup −1} in UF{sup +} and only 438 cm{sup −1} in UCl{sup +}. As in previous studies, the final PP-based SO-CASPT2 results for UF{sup +} and UF agree well with experiment and are expected to be predictive for UCl and UCl{sup +}, which are reported here for the first time.« less

Authors:
Publication Date:
OSTI Identifier:
22493227
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 143; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOMS; BORON PHOSPHIDES; COMPARATIVE EVALUATIONS; COMPRESSION; ELECTRON CORRELATION; ELECTRONS; EXCITED STATES; EXTRAPOLATION; GROUND STATES; HAMILTONIANS; MOLECULAR IONS; PERTURBATION THEORY; POTENTIALS; SPECTROSCOPY; SPIN; URANIUM CHLORIDES; URANIUM FLUORIDES

Citation Formats

Bross, David H., and Peterson, Kirk A., E-mail: kipeters@wsu.edu. Theoretical spectroscopy study of the low-lying electronic states of UX and UX{sup +}, X = F and Cl. United States: N. p., 2015. Web. doi:10.1063/1.4935492.
Bross, David H., & Peterson, Kirk A., E-mail: kipeters@wsu.edu. Theoretical spectroscopy study of the low-lying electronic states of UX and UX{sup +}, X = F and Cl. United States. https://doi.org/10.1063/1.4935492
Bross, David H., and Peterson, Kirk A., E-mail: kipeters@wsu.edu. Sat . "Theoretical spectroscopy study of the low-lying electronic states of UX and UX{sup +}, X = F and Cl". United States. https://doi.org/10.1063/1.4935492.
@article{osti_22493227,
title = {Theoretical spectroscopy study of the low-lying electronic states of UX and UX{sup +}, X = F and Cl},
author = {Bross, David H. and Peterson, Kirk A., E-mail: kipeters@wsu.edu},
abstractNote = {Spectroscopic constants (T{sub e}, r{sub e}, B{sub 0}, ω{sub e}, and ω{sub e}x{sub e}) have been calculated for the low-lying electronic states of UF, UF{sup +}, UCl, and UCl{sup +} using complete active space 2nd-order perturbation theory (CASPT2), with a series of correlation consistent basis sets. The latter included those based on both pseudopotential (PP) and all-electron Douglas-Kroll-Hess Hamiltonians for the U atom. Spin orbit (SO) effects were included a posteriori using the state interacting method using both PP and Breit Pauli (BP) operators, as well as from exact two-component methods for U{sup +} and UF{sup +}. Complete basis set (CBS) limits were obtained by extrapolation where possible and the PP and BP calculations were compared at their respective CBS limits. The PP-based method was shown to be reliable in calculating spectroscopic constants, in particular when using the state interacting method with CASPT2 energies (SO-CASPT2). The two component calculations were limited by computational resources and could not include electron correlation from the nominally closed shell 6s and 6p orbitals of U. UF and UCl were both calculated to have Ω = 9/2 ground states. The first excited state of UCl was calculated to be an Ω = 7/2 state at 78 cm{sup −1} as opposed to the same state at 435 cm{sup −1} in UF, and the other low-lying states of UCl showed a similar compression relative to UF. Likewise, UF{sup +} and UCl{sup +} both have Ω = 4 ground states and the manifold of low-lying excited Ω = 3, 2, 1, 0 states was energetically closer together in UCl{sup +} than in UF{sup +}, ranging up to 776 cm{sup −1} in UF{sup +} and only 438 cm{sup −1} in UCl{sup +}. As in previous studies, the final PP-based SO-CASPT2 results for UF{sup +} and UF agree well with experiment and are expected to be predictive for UCl and UCl{sup +}, which are reported here for the first time.},
doi = {10.1063/1.4935492},
url = {https://www.osti.gov/biblio/22493227}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 18,
volume = 143,
place = {United States},
year = {2015},
month = {11}
}

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    Works referencing / citing this record:

    Correlation consistent basis sets for lanthanides: The atoms La–Lu
    journal, August 2016


    Spectroscopic and theoretical studies of ThCl and ThCl +
    journal, February 2017