Knowledge Bank

Highly reliable ab initio techniques are combined with a phenomenological core polarization concept for an efficient treatment of intershell correlation effects in all-electron SCF/valence CI calculations. A single atomic parameter is sufficient to account quantitatively for intershell correlation effects on all atomic and molecular properties investigated. For ground states as well as a large number of excited states, the calculated spectroscopic constants agree with available experimental data to about $100cm-1$ for $De$ amd $Te$, to $1cm-1$ for $\Omega e$ and to 0.02 {\AA} for $Re$. Lifetimes appear to be accurate to better than 2%. Rydberg series and perturbations by doubly excited states are investigated for $Li2$ and $Na2$.