CORE-VALENCE CORRELATION ON THE LOW-LYING (1,3)F(O) TERMS OF CA-I

The excitation energies of the 3d4p F-1(o), 4s4f F-3(o), 3d4p F-1(o), and 4s4f F-1(o) states relative to the ground state 4s2 1S and the gro und-state ionization potential of neutral calcium (Ca I) are calculate d using a finite-element multiconfiguration Hartree-Fock method, throu gh the use of a systematic sequence of active spaces of increasing siz e. It is confirmed, through large-scale ab initio calculations, that a wrong position of the 3d4p perturber in the F-1(o) series, found in v alence multiconfiguration Hartree-Fock calculations, is due to the mis sing core-valence correlation. Some interference effects between core- valence and core-core correlation effects are also analyzed.