Binding properties of some alkali metal vapors: specifically lithium-7 (7Li), soduim-23 (23Na), and potassium-39 (39K)

Abstract

In this work, the binding energy of three alkali metal molecules, namely, lithium-7 (7Li2), sodium-23 (23Na2), and potassium-39 (39K2), is calculated in both free space and the vapor phase. In free space, the Lippmann–Schwinger equation is solved for negative-definite eigenenergies using a highly effective matrix-inversion method with a symmetrized kernel. In the vapor, two medium effects are taken into account: the effective atomic mass, which is somewhat larger than the “bare” mass and therefore enhances the binding; and the effective binary interaction, with less overall attraction than the “bare” interaction. In free space, the binding energies of the respective molecules are, in units of (103 K), 5.304, 2.936, and 2.522. The corresponding experimental results are 6.150 × 103, 4.275 ×103, and 4.275 × 103 K. The results in the vapor phase are by and large somewhat lower than those in free space.