Spectroscopic studies of the ground state dissociation energy and isotope shift of NaD

We report a spectroscopic measurement of the NaD X$^1\Sigma^+$ ground state dissociation energy and its isotope shift. Stimulated emission pumping with fluorescence depletion spectroscopy is applied to measure the rovibrational levels of the near-dissociation region. A total of 230 rovibrational levels in the range of $9\leq v'' \leq29$ and $1\leq J'' \leq11$ are observed and the highest vibrational level $v'' = 29$ is about 50 cm$^{-1}$ to the dissociation limit. Analyzing the highest 5 vibrational levels yields the dissociation energy $D_e$ =15822 $\pm$ 5 cm$^{-1}$ with $v_D$ = 31.2 $\pm$ 0.1. With our previous study, we are able to determine the difference in the well depths of this isotopologues, $D_e$ = $D_e$(NaH) - $D_e$(NaD) = -7 cm$^{-1}$.