Quasi-diabatic and adiabatic states and potential energy curves for Na-Cd collisions and excimer formation

We present the ab initio calculation of potential energy curves for the ground and excited electronic states of the NaCd system. Both quasi-diabatic and adiabatic wavefunctions and energies have been determined, by means of Quasi Degenerate Perturbation Theory (CIPSI algorithm). The spin-orbit coupling has been evaluated with two approximate methods: one is based on effective nuclear charges, the other one exploits the quasi-invariance of the diabatic states with respect to changes in the nuclear coordinate. The present results are relevant as to the interpretation of the emission spectra of the excimer NaCd*, and to the collisional dynamics of excited Na and Cd atoms.