Molecular Spectroscopy of Ultracold ^7Li Atoms

Fernanda B. V. Martins, James S. Keller

Bubai Rahaman, Satyabrata Baidya, Sourav Dutta

We describe an apparatus where many species of ultracold atoms can be simultaneously trapped and overlapped with many species of ions in a Paul trap. Several design innovations are made to increase the versatility of the apparatus while keeping the size and cost reasonable. We demonstrate the operation of a three-dimensional (3D) magneto-optical trap (MOT) of 7Li using a single external cavity diode laser. The 7Li MOT is loaded from an atomic beam, with atoms slowed using a Zeeman slower designed to work simultaneously for Li and Sr. The operation of a 3D MOT of 133Cs, loaded from a 2D MOT, is demonstrated, and provisions for MOTs of Rb and K in the same vacuum manifold exist. We demonstrate the trapping of 7Li+ and 133Cs+ at different settings of the Paul trap and their detection using an integrated time-of-flight mass spectrometer. We present results on low energy neutral-neutral collisions (133Cs-133Cs, 7Li-7Li, and 133Cs-7Li collisions) and charge-neutral collisions (133Cs+-133Cs and 7Li+-7Li collisions). We show evidence of sympathetic cooling of 7Li+ (133Cs+) due to collisions with the ultracold 7Li (133Cs).

John Lorenz, Adeel Altaf, Sourav Dutta +2 more

Amrendra Pandey, M Niranjan, N Joshi +2 more

Synopsis Accurate estimation of the scattering properties at the ultracold temperatures is challenging due to the demand for the precise knowledge of interactions between the colliding partners. We identify the aspects of interactions that play the defining roles in the scattering calculations. We compute potential energy curves for the 7Li+-7Li, X2∑g + and A2∑u +, and determine their collisional properties.

Paul S. Julienne

Joseph D. Miller, Robert A. Cline, D. J. Han +1 more

With the ultracold temperatures (T 1012 cm-3) of atoms that can be produced with laser-cooling and trapping techniques, it is now possible to carry out a new kind of high-resolution spectroscopy.1 This photoassociation is based on optical absorption resonances between the initially free states of colliding atoms and specific, bound excited molecular states. High resolution can be obtained because of the narrow energy distribution of the ultracold gas.1 Because the initial states are formed by collisions, it becomes possible to probe unique, excited molecular states with very large interatomic separations that are impossible to probe with conventional molecular spectroscopy. The feasibility of this new spectroscopy has been demonstrated in two recent experiments.2,3