Static dipole polarizabilities of Li2, Na2, and K2

Abstract

Static dipole polarizability functions (α_∥ and α_⊥) and thermally averaged isotropic polarizabilities (α) of Li₂, Na₂, and K₂ in their electronic ground states have been obtained from all‐electron SCF+valence CI calculations which include core polarization effects by use of an effective potential. As a function of internuclear separation, α_⊥ shows a monotonic increase in all three cases while α_∥ exhibits a pronounced maximum at about 1.5 R_e. For T=300 K, we find α(Li₂)=214, α(Na₂)=262, and α(K₂)=477 a.u. Our results, to which we attribute an uncertainty of 2%, support the measured value for the average polarizability of Li₂ [R. W. Molof et al., J. Chem. Phys. 6 1, 1816 (1974)] but disagree with their results for Na₂ and K₂. For these dimers, Molof ’s mean experimental values appear to be in error by 33% and 18%, respectively.