Ab initio prediction of the spectroscopic constants of NaN: Another potential candidate for a new Na-bearing interstellar molecule

Potential energy curves for the lowest 3Σ−, 3Π, 1Δ, and 5Σ− states of NaN have been calculated by the multireference singles and doubles configuration interaction method, including Davidson’s correction for quadruple excitations (MR-SDCI(+Q)). It is shown that the former three are bound states, while the last one has no minimum. The ground state of NaN is predicted to be 3Σ− for which the binding energy is evaluated as 0.859 eV, and the rotational constants are calculated as Be = 11.632 and B0 = 11.558 GHz. The spectroscopic constants presented here will help in the detection of NaN in interstellar space.