Superposition of Configurations and Natural Spin Orbitals. Applications to the He Problem

摘要: The method of superposition configurations is examined in its application to the helium atom two cases: a 21×21 matrix including all up 〈6s〉2, and 20×20 with 4‐quantum level, angular terms. A new radial limit established at −2.87900±0.00003, this used discuss convergence such expansions Legendie functions. variation scale factor discussed detail. wave functions are analyzed terms natural spin orbitals (NSO's), which seem have many advantages. first NSO bears striking resemblance Hartree‐Fock function, together provide close approximation solution extended equations different for electrons. An energy −2.877924 obtained best (u, v) function found. analysis results suggests that inner may be better represented by pure exponentials than whenever additional correlational degrees freedom permitted. Expressed approximate form, almost invariant choice basis set, provided latter reasonably chosen. In particular, necessity continuum along discrete hydrogen‐like set demonstrated.