High resolution laser spectroscopy of the B 1Π–X 1Σ+ transition of 23Na85Rb

Abstract

High resolution spectrum of the B 1Π–X 1Σ+ transition of the NaRb molecule was measured with the technique of the Doppler-free laser polarization spectroscopy. Molecular constants of the B 1Π(v=0–12) and X 1Σ+(v=0–6) states of 23Na85Rb were determined. The energy levels of the B 1Π state were found to present many irregularities due to perturbations. The resonance fluorescence spectrum following an excitation to a strongly perturbed level was measured. The fluorescence to the (1)3Σ+ state, which consists of discrete lines followed by a continuum band, was observed in addition to the fluorescence lines to rovibrational levels of the X 1Σ+ state. The perturbing state to the B 1Π(v=8,J=15–21) levels is identified as the (1)3Π state by comparing the observed fluorescence spectra with the selection rules for perturbations and radiative transitions. The dissociation limit of the (1)3Σ+ state, which separates into the Na(3s2S1/2)+Rb(5s2S1/2) atoms, was deduced from the spectrum. The dissociation energies of the X 1Σ+, (1)3Σ+, and B 1Π states were determined to be 5030±2, 182±2, and 1319±2 cm−1, respectively.

Long-range states of the NaRb molecule near theNa(3 2S1/2)+Rb(5 Zhu1, Li2, He3 et al. 2016Phys. Rev. A110110View full textAdd to dashboardCite

“…With a properly designed two-photon stimulated Raman process, the weakly-bound molecules formed can be transferred to the lowest energy level of the molecular ground state with the high initial phase-space density preserved [7][8][9]. This was successfully implemented for 40 K 87 Rb molecule [10] in 2008, and very recently for 87 Rb 133 Cs [11,12] and 23 Na 40 K [13] molecules. For 40 K 87 Rb, two-body chemical reaction can happen, which induces large inelastic losses [14,15].…”

“…The bosonic 23 Na 87 Rb molecule in its ground state is also chemically stable against two-body collisions [16]. Besides, it possesses a permanent electric dipole moment of 3.3 Debye, larger than all the aforementioned molecules [18].…”

“…Recently, we have successfully produced 23 Na 87 Rb Fesh-bach molecules by sweeping the magnetic field across a Feshbach resonance [21]. The next critical step for making ground-state 23 Na 87 Rb molecules is to find a path for an efficient stimulated Raman process. As illustrated in Fig.1, the internuclear distances between the ground-state and the Feshbach molecules are vastly different.…”

“…It is thus another important candidate for investigating ultracold polar molecules. In the past two years, we have prepared an ultracold mixture of 23 Na and 87 Rb [19] and studied their Feshbach resonances [20]. Recently, we have successfully produced 23 Na 87 Rb Fesh-bach molecules by sweeping the magnetic field across a Feshbach resonance [21].…”

“…In the past two years, we have prepared an ultracold mixture of 23 Na and 87 Rb [19] and studied their Feshbach resonances [20]. Recently, we have successfully produced 23 Na 87 Rb Fesh-bach molecules by sweeping the magnetic field across a Feshbach resonance [21]. The next critical step for making ground-state 23 Na 87 Rb molecules is to find a path for an efficient stimulated Raman process.…”