MULTICONFIGURATION EFFECTIVE POTENTIAL CALCULATION OF THE SPECTROSCOPIC CONSTANTS OF $Pb_{2}$

Abstract

A theory of general effective potentials applicable to MCSCF calculations is outlined. As a test case, the ground state of $Pb_{2}$ has been studied, both with and without relativistic corrections. Ab initio values of $r_{e}, \omega_{e}, \omega_{e}x_{e}$ and the value of $D_{e}$ corresponding to dissociation to two $^{3}{P_{_{o}}}$ atoms are reported. Although direct relativistic effects are large, the indirect effects are small compared to electron correlation. For the ground state the nonrelativistic approximation gives good agreement with available experimental results.