NATURAL SPIN ORBITAL ANALYSIS OF DIATOMIC MOLECULAR WAVE-FUNCTIONS IN TERMS OF GENERALIZED DIATOMIC ORBITALS .3. VARIABLE SCREENING MODELS FOR SOME EXCITED-STATES OF HEH+

The original idea of the model applied to HeH+ excited states is: One electron occupies a diatomic orbital similar to the HeH++ ground state 1 sσ function. The other electron occupies an orbital which can be represented by a linear combination of functions similar to H2+excited state functions. One or two screening parameters are variationally optimized to compensate for the smallness of the one-electron basis. CI calculations have been performed for five excited HeH+ states covering a wide range of internuclear distances. The CI wave functions have been submitted to a natural spin orbital analysis. The strongly occupied NSOs are compared with the original model functions. © 1979 Springer-Verlag.