Experimental Studies of NaCs

We present experimental studies of excited electronic states of the NaCs molecule that are currently underway in our laboratory. The optical-optical double resonance method is used to obtain Doppler-free excitation spectra for several excited states. These data are being used to obtain Rydberg-Klein-Rees (RKR) or Inverse Perturbation Approach (IPA) potential curves for these states. We are also trying to map the bound portion of the 1($a)^{3}\Sigma ^{+}$ potential using resolved laser-induced fluorescence and Fourier transform spectroscopy to record transitions into the shallow well. Bound-free spectra from single ro-vibrational levels of electronically excited states to the repulsive wall of the 1($a)^{3}\Sigma ^{+}$ state are also being recorded. Using the previously determined excited state potentials, we can fit the repulsive wall of the 1($a)^{3}\Sigma ^{+}$ state to reproduce the experimental spectra using LeRoy's BCONT program. A slightly modified version of BCONT will also be used to fit the relative transition dipole moments, \textit{$\mu $}$_{e}(R)$, as a function of internuclear separation $R$, for the various bound-free electronic transitions.