Short-range photoassociation of LiRb

We have observed short-range photoassociation of Li7Rb85 to the two lowest vibrational states of the d3Π potential. We have also observed several a3Σ+ vibrational levels with generation rates between ∼102 and ∼103 molecules per second, resulting from the spontaneous decay of these d3Π molecules. We observe an alternation of the peak heights in the rotational photoassociation spectrum that depends on the parity of the excited molecular state. Franck-Condon overlap calculations predict that photoassociation to higher vibrational levels of the d3Π potential, in particular, the sixth vibrational level, should populate the lowest vibrational level of the a3Σ+ state at a rate as high as 104 molecules per second. This work also motivates an experimental search for short-range photoassociation to other bound molecular states, such as c3Σ+ or b3Π, as prospects for preparing ground-state molecules.