A hybrid configuration interaction treatment based on seniority number and excitation schemes

ALCOBA, DIEGO R.; TORRE, ALICIA; LAIN, LUIS; OÑA, OFELIA B.; CAPUZZI, PABLO; VAN RAEMDONCK, MARIO; BULTINCK, PATRICK; VAN NECK, DIMITRI

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Año: 2014 vol. 141

0021-9606

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 describesystems 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.