The <i>a</i> 3Σ+ state of NaK. High resolution spectroscopy using laser-induced fluorescence (LIF)

Abstract

We use laser-induced fluorescence (LIF) combined with a high resolution grating spectrometer to study the D 1Π→a 3Σ+ transitions of the heteronuclear alkali dimer NaK. Intense perturbations of the D 1Π state permit high resolution measurements and facilitate study of the corresponding intensities. From these spectra, we evaluate the molecular constants of the a 3Σ+ state of NaK and estimate the parameters involved in the perturbations of the D 1Π state. Various features of the perturbing levels are discussed. We compare the results of our analysis with the results of spin-exchange scattering experiments on the NaK system and with theoretical calculations. In addition, very accurate dissociation energies, De(NaK, 1Σ+) =5268.1±0.8 cm−1 and De(NaK, a 3Σ+) =203.1±0.5 cm−1, are obtained.