Controlling the N - And S -representability of the second-order reduced density matrix: The doublet-state case

• Autores: Alcoba, Diego Ricardo; Valdemoro, C; Tel, L. M.; Perez Romero, E.
• Año de publicación: 2008
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: -
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

A purification procedure that simultaneously corrects the N - and S -representability main defects of a second-order reduced density matrix (2RDM), second-order hole reduced density matrix (2HRDM), and second-order G matrix is presented here. In this purifying procedure, the generalized unitarily invariant second-order matrix decomposition for the 2RDM and the 2HRDM as well as for the G matrix is combined with the S -representability conditions. In particular, here we will focus our attention on the RDMs corresponding to doublet states. We will thus explicitly give the S -representability conditions that a two-body correlation matrix has to satisfy when an N -electron system is in a doublet spin-state in the spin-component of maximum projection. Furthermore, as a consequence of the G -matrix spin properties (which directly affect the S -representability of the 2RDM), we show that a different contracting form for the 2RDM is possible. The numerical results presented in this work confirm the efficiency of our purifying procedure. © 2008 The American Physical Society.
Fil: Alcoba, Diego Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina
Fil: Valdemoro, C. Csic - Instituto de Matematicas y Fisica Fundamental; España
Fil: Tel, L. M.. Universidad de Salamanca; España
Fil: Perez Romero, E.. Universidad de Salamanca; España