title: A hybrid configuration interaction treatment based on seniority number and excitation schemes.
abstract: We present a configuration interaction method in which the Hamiltonian of an N-electron system is projected on Slater determinants selected according to the seniority-number criterion along with the traditional excitation-based procedure. This proposed method is especially useful to describe systems which exhibit dynamic (weak) correlation at determined geometric arrangements (where the excitation-based procedure is more suitable) but show static (strong) correlation at other arrangements (where the seniority-number technique is preferred). The hybrid method amends the shortcomings of both individual determinant selection procedures, yielding correct shapes of potential energy curves with results closer to those provided by the full configuration interaction method.
authors.affiliation: Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Física de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
authors.forename: Diego R
authors.initials: DR
authors.lastname: Alcoba
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644 E-48080 Bilbao, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Torre
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644 E-48080 Bilbao, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Lain
authors.affiliation: Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Universidad Nacional de La Plata, CCT La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, Diag. 113 y 64 (S/N), Sucursal 4, CC 16, 1900 La Plata, Argentina.
authors.forename: Ofelia B
authors.initials: OB
authors.lastname: Oña
authors.affiliation: Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Física de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
authors.forename: Pablo
authors.initials: P
authors.lastname: Capuzzi
authors.affiliation: Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3), 9000 Gent, Belgium.
authors.forename: Mario
authors.initials: M
authors.lastname: Van Raemdonck
authors.affiliation: Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3), 9000 Gent, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Bultinck
authors.affiliation: Center for Molecular Modelling, Ghent University, Technologiepark 903, 9052 Zwijnaarde, Belgium.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Van Neck