Analytic potential functions for weakly bound molecules: The X and A states of NaAr and the A state of NaNe

The interatomic potential functions for the ground and first excited electronic states of the weakly bound molecule NaAr and the first excited state of NaNe are derived by inverting spectral data to analytic potential functions. Using the Thakkar potential expansion, it is shown how one may deduce vibrational assignments, compute accurate dissociation energies, and combine two potentials with an atomic transition to advantage. The resulting potential functions are in excellent agreement not only with spectroscopic data, but also with potentials derived from scattering and atomic resonance line broadening experiments.