Ground-state properties of alkali dimers and their cations (including the elements Li, Na, and K) from a b i n i t i o calculations with effective core polarization potentials

Abstract

Extensive all‐electron SCF and valence CI calculations are presented for alkali dimer systems with consideration of intershell correlation effects by use of an effective core polarization potential (CPP), which contains only a single adjustable atomic parameter. High accuracy is obtained for the ground‐state spectroscopic constants of the studied molecules. The maximum deviations from accurate experimental data are as follows: 1% or 0.03 Å for R_e, 2% or 100 cm⁻¹ for D_e, 0.5% or 1 cm⁻¹ for ω_e, and 0.2% or 100 cm⁻¹ for ionization energies. For experimentally uncertain or unknown values reliable predictions can thus be made. The calculated dipole moments for LiK and NaK agree with experiment to within 0.1%, but for LiNa we obtain a deviation of 8% or 0.036 D. An analysis of molecular core polarization contributions reveals the reasons for some systematic defects in previous pseudopotential calculations.