Artículos de revistas
Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions
Fecha
2013-08-23Registro en:
Alcoba, Diego Ricardo; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo Ernesto; Oña, Ofelia Beatriz; Seniority number in spin-adapted spaces and compactness of configuration interaction wave functions; American Institute of Physics; Journal of Chemical Physics; 139; 8; 23-8-2013; 84103-85103
0021-9606
Autor
Alcoba, Diego Ricardo
Torre, Alicia
Lain, Luis
Massaccesi, Gustavo Ernesto
Oña, Ofelia Beatriz
Resumen
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.