Approximate singly excited states from a twocomponent HartreeFock reference
For many molecules, relaxing the spin symmetry constraint on the wave function results in the lowest energy meanfield solution. The twocomponent HartreeFock (2cHF) method relaxes all spin symmetry constraints, and the wave function is no longer an eigenfunction of the total spin, spin projection, or timereversal symmetry operators. For ground state energies, 2cHF is a superior meanfield method for describing spinfrustrated molecules. For excited states, the utility of 2cHF is uncertain. Here, we implement the 2cHF extensions of two singlereference excited state methods, the twocomponent configuration interaction singles and timedependent HartreeFock. In this, we compare the results to the analogous methods based off of the unrestricted HartreeFock approximation, as well as the full configuration interaction for three small molecules with distinct 2cHF solutions, and discuss the nature of the 2cHF excited state solutions.
 Authors:

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 Univ. of Washington, Seattle, WA (United States). Dept. of Chemistry
 Publication Date:
 Grant/Contract Number:
 SC0006863; CHE1265945; DGE1256082
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of Chemical Physics
 Additional Journal Information:
 Journal Volume: 143; Journal Issue: 14; Journal ID: ISSN 00219606
 Publisher:
 American Institute of Physics (AIP)
 Research Org:
 Univ. of Washington, Seattle, WA (United States)
 Sponsoring Org:
 USDOE Office of Science (SC); National Science Foundation (NSF); Gaussian, Inc., Wallingford, CT (United States)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; particle symmetry; slater determinant; functional equations; full configuration interaction; oscillator strengths; chemical elements; excitation energies; zero point energy; self consistent field methods; leptons
 OSTI Identifier:
 1469476
 Alternate Identifier(s):
 OSTI ID: 1223328
Goings, Joshua J., Ding, Feizhi, Davidson, Ernest R., and Li, Xiaosong. Approximate singly excited states from a twocomponent HartreeFock reference. United States: N. p.,
Web. doi:10.1063/1.4932540.
Goings, Joshua J., Ding, Feizhi, Davidson, Ernest R., & Li, Xiaosong. Approximate singly excited states from a twocomponent HartreeFock reference. United States. doi:10.1063/1.4932540.
Goings, Joshua J., Ding, Feizhi, Davidson, Ernest R., and Li, Xiaosong. 2015.
"Approximate singly excited states from a twocomponent HartreeFock reference". United States.
doi:10.1063/1.4932540. https://www.osti.gov/servlets/purl/1469476.
@article{osti_1469476,
title = {Approximate singly excited states from a twocomponent HartreeFock reference},
author = {Goings, Joshua J. and Ding, Feizhi and Davidson, Ernest R. and Li, Xiaosong},
abstractNote = {For many molecules, relaxing the spin symmetry constraint on the wave function results in the lowest energy meanfield solution. The twocomponent HartreeFock (2cHF) method relaxes all spin symmetry constraints, and the wave function is no longer an eigenfunction of the total spin, spin projection, or timereversal symmetry operators. For ground state energies, 2cHF is a superior meanfield method for describing spinfrustrated molecules. For excited states, the utility of 2cHF is uncertain. Here, we implement the 2cHF extensions of two singlereference excited state methods, the twocomponent configuration interaction singles and timedependent HartreeFock. In this, we compare the results to the analogous methods based off of the unrestricted HartreeFock approximation, as well as the full configuration interaction for three small molecules with distinct 2cHF solutions, and discuss the nature of the 2cHF excited state solutions.},
doi = {10.1063/1.4932540},
journal = {Journal of Chemical Physics},
number = 14,
volume = 143,
place = {United States},
year = {2015},
month = {10}
}