Photoassociation of ultracold LiRb* molecules: observation of high efficiency and unitarity-limited rate saturation

الأصل · EN

We report the production of ultracold heteronuclear 7Li85Rb molecules in excited electronic states by photoassociation (PA) of ultracold 7Li and 85Rb atoms. PA is performed in a dual-species 7Li-85Rb magneto-optical trap (MOT) and the PA resonances are detected using trap loss spectroscopy. We identify several strong PA resonances below the Li (2s 2S1/2) + Rb (5p 2P3/2) asymptote and experimentally determine the long range C6 dispersion coefficients. We find a molecule formation rate (PₗiRb) of 3.5x10⁷ s-1 and a PA rate coefficient (KₚA) of 1.3x10-10 cm³/s, the highest among heteronuclear bi-alkali molecules. At large PA laser intensity, we observe the saturation of the PA rate coefficient (KₚA) close to the theoretical value at the unitarity limit.