A comprehensive theoretical investigation of the electronic states of Ca-2 up to the Ca(4s(2) S-1)+Ca(4s5p P-1) dissociation limit

作者：Bouissou Thomas^*; Durand Gerard; Heitz Marie Catherine; Spiegelman Fernand

来源：Journal of Chemical Physics, 2010, 133(16): 164317.

DOI：10.1063/1.3503655

A theoretical survey of the electronic structure of Ca-2 is presented using two-electron pseudopotentials complemented by core-polarization operators on Ca atoms and multireference configuration interaction/quasidegenerate perturbation theory (MRCI/QDPT) treatment of molecular excited states. The spectroscopic constants of 70 electronic states up to 30 000 cm(-1) above the ground state are determined. This implies all Ca-2 states dissociating up to the Ca(4s(2) S-1)+Ca(4s5p P-3,P-1) dissociation limits. All spin states (singlet, triplet, and quintet) are investigated. The work emphasizes the variety of interactions implying singly valence and lowest Rydberg excited states, doubly excited states generated by atom pairs P-3(4s4p)+P-3(4s4p), or P-3(4s4p)+D-3(4s3d), 4p3d double excitations asymptotically localized on a single-atom. Zwitterionic Ca++Ca- configurations are evidenced and shown to induce specific electronic patterns in (1)Sigma(+)(g), (3)Sigma(+)(g), (1)Sigma(+)(u), (3)Sigma(+)(u), (1)Pi(g), (3)Pi(g), (1)Pi(u), and (3)Pi(u) symmetry manifolds. They also provide insight for qualitative features (barriers) found for the lower electronic states already investigated in previous publications by other authors.

• 出版日期2010-10-28