Dissociation energy of alkali metal clusters related to inhomogeneous electron gas theory

Abstract

A pseudopotential model, combined with a one-centre expansion, is set up to calculate the dissociation energies D of alkali metal atom clusters Li N to Cs N , when 2 ˇ- N ˇ- 10. This central field model is solved for the valence electrons using the Slater-Kohn-Sham (SKS) equations, with a local density approximation for the exchange-correlation one-body potential. Inhomogeneous electron gas theory, in terms only of the valence electron ground-state density ϱ, is then utilized, with ϱ constructed from the SKS wavefunctions, to relate D/N to the inhomogeneity kinetic energy T 2 of the equilibrium cluster. For N ranging from 3 to 10, a global correlation is demonstrated, with D/N ≈ T 2. A correlation between D and the density ϱ at the (equivalent) bond midpoints in the clusters is also exposed.