DISSOCIATION-ENERGY OF ALKALI-METAL CLUSTERS RELATED TO INHOMOGENEOUS ELECTRON-GAS THEORY

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 less-than-or-equal-to N less-than-or-equal-to 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 rho, is then utilized, with rho constructed from the SKS wavefunctions, to relate D/N to the inhomogeneity kinetic energy T2 of the equilibrium cluster. For N ranging from 3 to 10, a global correlation is demonstrated, with D/N almost-equal-to T2. A correlation between D and the density rho at the (equivalent) bond midpoints in the clusters is also exposed.