Long range potentials for two Na3p atoms including ionic-covalent interaction and fine structure: Application to two-color photoassociation spectroscopy.

Abstract

In the framework of ab initio pseudopotential calculations, a method is presented to compute an effective spin-orbit Hamiltonian within a nonorthogonal diabatic representation separating the ionic and covalent subspaces. The resulting Hund's case c adiabatic curves display long range structures. We predict that a small $(\ensuremath{\approx}1{\mathrm{cm}}^{\ensuremath{-}1})$ fine-structure splitting of an ionic $^{3}\ensuremath{\Pi}_{u}$ curve is manifested in the spectrum of the excited N${\mathrm{a}}_{2}$ molecule slightly below the $(3p^{2}P_{1/2}+3p^{2}P_{1/2})$ asymptote as a series of well identified quadruplets. They should be observed in two-color photoassociation spectroscopy experiments using cold atoms.