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

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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.
Formato:	Artículo publishedVersion
Publicado:	2013
Materias:	Change of basis Configuration interactions Expectation values Natural orbitals Quantitative evaluation Rapid convergence Slater determinants Unitary transformations Electrospinning Magnetic moments Molecular orbitals Wave functions
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00219606_v139_n8_p_Alcoba_oai
Aporte de:	Repositorio Digital de la Universidad de Buenos Aires (UBA) de Universidad de Buenos Aires

id	I28-R145-paper_00219606_v139_n8_p_Alcoba_oai
record_format	dspace
spelling	I28-R145-paper_00219606_v139_n8_p_Alcoba_oai2020-10-19 Alcoba, D.R. Torre, A. Lain, L. Massaccesi, G.E. Oña, O.B. 2013 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. application/pdf http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar J Chem Phys 2013;139(8) Change of basis Configuration interactions Expectation values Natural orbitals Quantitative evaluation Rapid convergence Slater determinants Unitary transformations Electrospinning Magnetic moments Molecular orbitals Wave functions Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00219606_v139_n8_p_Alcoba_oai
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-145
collection	Repositorio Digital de la Universidad de Buenos Aires (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	Artículo Artículo publishedVersion
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
publishDate	2013
url	http://hdl.handle.net/20.500.12110/paper_00219606_v139_n8_p_Alcoba http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00219606_v139_n8_p_Alcoba_oai
work_keys_str_mv	AT alcobadr senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions AT torrea senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions AT lainl senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions AT massaccesige senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions AT onaob senioritynumberinspinadaptedspacesandcompactnessofconfigurationinteractionwavefunctions
_version_	1766026574024409088

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

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