Hyperfine Analysis of the Excited States and Continuous Production of the Lowest Rovibronic Gro

by Prof. Jin-Tae Kim (Chosun University, 조선대학교 광기술공학과)

Thursday Sep 7, 2017, 4:30 PM → 5:30 PM Asia/Seoul

206호 (제1과학관)

Short-range photoassociation (PA), which produces continuously ultracold 85Rb133Cs molecules in the lowest rovibronic ground level X 1S+ (v = 0, J = 0), has opened up to investigate various hyperfine structures of deeply bound rovibrational levels in the strongly perturbed regions. Electronic states with strong singlet-triplet mixing can be useful for efficient direct molecule production in the rovibronic ground state via short-range PA. 85Rb and 133Cs atoms trapped in their |FRb=2> and |FCs=3> hyperfine states in dark SPOT MOTs were photoassociated into excited molecular states, which decay into the electronic ground state by spontaneous emission.
We have investigated deeply bound short-range PA lines of the B 1P (W = 1), c 3S+ (W = 0- and 1), and b 3P (W = 0-, 0+, and 1) states and the 2 1P(W = 1), 3 3S+(W = 1), and 2 3P(W = 1) states [1] of 85Rb133Cs dissociating into the 5s(Rb) + 6p(Cs) and 6s(Cs) + 5p(Rb) limits, respectively.
Rich hyperfine structures of those electronic states with the low J which were not observed in molecular beam [2] and the FTS [3], respectively have been explained mainly considering nuclear spin-electron orbital angular momentum, Fermi-contact, and dipolar electron spin-nuclear spin interactions. Through triplet-singlet spin-orbit electronic mixings, the singlet state often has larger HFS splittings and shows HFS structure like a triplet state unexpectedly although there is no electronic spin. Analysis of the hyperfine structures makes it possible to assign vibrational levels of singlet and triplet states which were not assigned due to strong spin-orbit interaction.
For selected PA levels, vibrational branching and rotational branching in the X 1S+ (v = 0) state have been investigated using resonance-enhanced multiphoton ionization and depletion spectroscopy [4], respectively. Efficient production of the rovibronic ground level X 1S+ (v = 0, J = 0) has been observed for some of the PA levels. Molecule production rate up to ~1×104 molecules /s into the lowest rovibronic ground level has been achieved.