Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions

This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and per...

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Autores principales: Alcoba, D.R., Torre, A., Lain, L., Massaccesi, G.E., Oña, O.B.
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba
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spelling todo:paper_00219606_v139_n8_p_Alcoba2023-10-03T14:24:31Z Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions Alcoba, D.R. Torre, A. Lain, L. Massaccesi, G.E. Oña, O.B. Change of basis Configuration interactions Expectation values Natural orbitals Quantitative evaluation Rapid convergence Slater determinants Unitary transformations Electrospinning Magnetic moments Molecular orbitals Wave functions This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and perform a study on the behavior of the expectation values of this operator under transformations of the molecular basis sets. This study leads to propose a quantitative evaluation for the convergence of the expansions of the wave functions in terms of Slater determinants. The non-invariant character of the seniority number operator expectation value of a wave function with respect to a unitary transformation of the molecular orbital basis set, allows us to search for a change of basis which minimizes that expectation value. The results found in the description of wave functions of selected atoms and molecules show that the expansions expressed in these bases exhibit a more rapid convergence than those formulated in the canonical molecular orbital bases and even in the natural orbital ones. © 2013 AIP Publishing LLC. 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. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_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 Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
spellingShingle Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
Alcoba, D.R.
Torre, A.
Lain, L.
Massaccesi, G.E.
Oña, O.B.
Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
topic_facet Change of basis
Configuration interactions
Expectation values
Natural orbitals
Quantitative evaluation
Rapid convergence
Slater determinants
Unitary transformations
Electrospinning
Magnetic moments
Molecular orbitals
Wave functions
description This work extends the concept of seniority number, which has been widely used for classifying N-electron Slater determinants, to wave functions of N electrons and spin S, as well as to N-electron spin-adapted Hilbert spaces. We propose a spin-free formulation of the seniority number operator and perform a study on the behavior of the expectation values of this operator under transformations of the molecular basis sets. This study leads to propose a quantitative evaluation for the convergence of the expansions of the wave functions in terms of Slater determinants. The non-invariant character of the seniority number operator expectation value of a wave function with respect to a unitary transformation of the molecular orbital basis set, allows us to search for a change of basis which minimizes that expectation value. The results found in the description of wave functions of selected atoms and molecules show that the expansions expressed in these bases exhibit a more rapid convergence than those formulated in the canonical molecular orbital bases and even in the natural orbital ones. © 2013 AIP Publishing LLC.
format JOUR
author Alcoba, D.R.
Torre, A.
Lain, L.
Massaccesi, G.E.
Oña, O.B.
author_facet Alcoba, D.R.
Torre, A.
Lain, L.
Massaccesi, G.E.
Oña, O.B.
author_sort Alcoba, D.R.
title Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_short Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_full Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_fullStr Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_full_unstemmed Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
title_sort seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
url http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba
work_keys_str_mv AT alcobadr senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
AT torrea senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
AT lainl senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
AT massaccesige senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
AT onaob senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
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