Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment

This work deals with the spin contamination in N-electron wave functions provided by the excitation-based configuration interaction methods. We propose a procedure to ensure a suitable selection of excited N-electron Slater determinants with respect to a given reference determinant, required in thes...

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Autores principales: Alcoba, D.R., Torre, A., Lain, L., Massaccesi, G.E., Oña, O.B., Capuzzi, P.
Formato: JOUR
Materias:
Eigenvalues and eigenfunctions
Electrons
Numerical methods
Quantum chemistry
Wave functions
Computational costs
Configuration interaction method
Configuration interactions
Excitation operators
Expectation values
N-electron wave function
Slater determinants
Spin contamination
Excited states
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00219606_v145_n1_p_Alcoba
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00219606_v145_n1_p_Alcoba
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spelling todo:paper_00219606_v145_n1_p_Alcoba2023-10-03T14:24:36Z Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment Alcoba, D.R. Torre, A. Lain, L. Massaccesi, G.E. Oña, O.B. Capuzzi, P. Eigenvalues and eigenfunctions Electrons Numerical methods Quantum chemistry Wave functions Computational costs Configuration interaction method Configuration interactions Excitation operators Expectation values N-electron wave function Slater determinants Spin contamination Excited states This work deals with the spin contamination in N-electron wave functions provided by the excitation-based configuration interaction methods. We propose a procedure to ensure a suitable selection of excited N-electron Slater determinants with respect to a given reference determinant, required in these schemes. The procedure guarantees the construction of N-electron wave functions which are eigenfunctions of the spin-squared operator S 2, avoiding any spin contamination. Our treatment is based on the evaluation of the excitation level of the determinants by means of the expectation value of an excitation operator formulated in terms of spin-free replacement operators. We report numerical determinations of energies and S 2 expectation values, arising from our proposal as well as from traditional configuration interaction methods, in selected open-shell systems, in order to compare the behavior of these procedures and their computational costs. © 2016 Author(s). Fil:Massaccesi, G.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Oña, O.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Capuzzi, P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00219606_v145_n1_p_Alcoba
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Eigenvalues and eigenfunctions
Electrons
Numerical methods
Quantum chemistry
Wave functions
Computational costs
Configuration interaction method
Configuration interactions
Excitation operators
Expectation values
N-electron wave function
Slater determinants
Spin contamination
Excited states
spellingShingle Eigenvalues and eigenfunctions
Electrons
Numerical methods
Quantum chemistry
Wave functions
Computational costs
Configuration interaction method
Configuration interactions
Excitation operators
Expectation values
N-electron wave function
Slater determinants
Spin contamination
Excited states
Alcoba, D.R.
Torre, A.
Lain, L.
Massaccesi, G.E.
Oña, O.B.
Capuzzi, P.
Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment
topic_facet Eigenvalues and eigenfunctions
Electrons
Numerical methods
Quantum chemistry
Wave functions
Computational costs
Configuration interaction method
Configuration interactions
Excitation operators
Expectation values
N-electron wave function
Slater determinants
Spin contamination
Excited states
description This work deals with the spin contamination in N-electron wave functions provided by the excitation-based configuration interaction methods. We propose a procedure to ensure a suitable selection of excited N-electron Slater determinants with respect to a given reference determinant, required in these schemes. The procedure guarantees the construction of N-electron wave functions which are eigenfunctions of the spin-squared operator S 2, avoiding any spin contamination. Our treatment is based on the evaluation of the excitation level of the determinants by means of the expectation value of an excitation operator formulated in terms of spin-free replacement operators. We report numerical determinations of energies and S 2 expectation values, arising from our proposal as well as from traditional configuration interaction methods, in selected open-shell systems, in order to compare the behavior of these procedures and their computational costs. © 2016 Author(s).
format JOUR
author Alcoba, D.R.
Torre, A.
Lain, L.
Massaccesi, G.E.
Oña, O.B.
Capuzzi, P.
author_facet Alcoba, D.R.
Torre, A.
Lain, L.
Massaccesi, G.E.
Oña, O.B.
Capuzzi, P.
author_sort Alcoba, D.R.
title Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment
title_short Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment
title_full Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment
title_fullStr Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment
title_full_unstemmed Spin contamination-free N -electron wave functions in the excitation-based configuration interaction treatment
title_sort spin contamination-free n -electron wave functions in the excitation-based configuration interaction treatment
url http://hdl.handle.net/20.500.12110/paper_00219606_v145_n1_p_Alcoba
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AT torrea spincontaminationfreenelectronwavefunctionsintheexcitationbasedconfigurationinteractiontreatment
AT lainl spincontaminationfreenelectronwavefunctionsintheexcitationbasedconfigurationinteractiontreatment
AT massaccesige spincontaminationfreenelectronwavefunctionsintheexcitationbasedconfigurationinteractiontreatment
AT onaob spincontaminationfreenelectronwavefunctionsintheexcitationbasedconfigurationinteractiontreatment
AT capuzzip spincontaminationfreenelectronwavefunctionsintheexcitationbasedconfigurationinteractiontreatment
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