Spin-forbiddenc3Σ+(Ω=1)←X1Σ+transition in NaCs: Investigation of theΩ=1state in hot and cold environments

Abstract

Comprehensive spectroscopic studies of hot and ultracold samples of NaCs molecules were combined to complete the investigation of the $(3)\ensuremath{\Omega}=1$ $\ensuremath{\leftarrow}$ $X$ ${}^{1}{\ensuremath{\Sigma}}^{+}$ transition for the NaCs molecule. Polarization labeling, photoassociation, and pulsed laser depletion spectroscopy were used to collect data on rovibrational levels of the $(3)\ensuremath{\Omega}=1$ state [here described as the $c$ ${}^{3}{\ensuremath{\Sigma}}^{+}$ state in Hund's case (a) notation]. The highest observed level was $v=72$ located $~$5 GHz below the atomic asymptote Na($3{ }^{2}{S}_{1/2}$) $+$ Cs($6{ }^{2}{P}_{3/2}$). Approximately 1400 levels were used to construct the potential energy curve of the $(3)\ensuremath{\Omega}=1$ state for the full range of interatomic distances.