We have observed short-range photoassociation of LiRb to the two lowest vibrational states of the d 3 Π potential. These d 3 Π molecules then spontaneously decay to vibrational levels of the a 3 Σ + state with generation rates of ∼ 10 3 molecules per second. This is the first observation of many of these a 3 Σ + levels. We observe an alternation of the peak heights in the rotational photoassociation spectrum that suggests a p-wave shape resonance in the scattering state. Franck-Condon overlap calculations predict that photoassociation to higher vibrational levels of the d 3 Π, in particular the sixth vibrational level, should populate the lowest vibrational level of the a 3 Σ + state with a rate as high as 10 4 molecules per second. These results encourage further work to explain our observed LiRb collisional physics using PECs. This work also motivates an experimental search for short-range photoassociation to other bound molecules, such as the c 3 Σ + or b 3 Π, as prospects for preparing ground-state molecules.Heteronuclear bi-alkali molecules in the X 1 Σ + or a 3 Σ + electronic potentials are interesting both experimentally and theoretically for a number of reasons. Experimentally, they have long lifetimes and large, permanent electric dipole moments. Significant effort has been dedicated to the study of dipolar molecules [1-3], in part because permanent electric dipole moments give rise to interesting long-range and anisotropic interactions [4]. For example, dipolar bosons may exhibit a pair supersolid phase [5], and enhance [6] or destabilize [7] superfluidity. They have been proposed as qubits for quantum computation [8,9], which, under certain conditions, could exhibit high fidelity [10]. Trapped ensembles of heteronuclear bi-alkali molecules could also exhibit novel few-body [11] and many-body interactions [12][13][14]. Such molecules could even be used to probe for variation of fundamental constants [15].The first step in any experimental realization is, of course, the creation of the ultracold heteronuclear bialkali molecules themselves. Two preparation methods stand out in particular: magnetoassociation followed by Stimulated Raman Adiabatic Passage (STIRAP) [16], and photoassociation (PA) followed by spontaneous emission [17,18]. The PA method is experimentally simpler (as it only involves one laser), but it relies on finding an excited state that decays preferentially to the desired final state. To extend the study of the rich physics offered by ultracold heteronuclear bi-alkali molecules, various preparation methods must be evaluated in a variety of systems. In this work using ultracold LiRb, we have evaluated one pathway to create a 3 Σ + molecules, namely PA of atoms to the d 3 Π molecular state.Photoassociation is the process where unbound atoms, colliding in the presence of light, can absorb a photon and bind into an electronically excited state molecule. In order to have a significant probability for this pro- * These two authors contributed equally † Corresponding author: David Blasing, dblas...

We report on a resonantly coupled 2(1) -4 (1) photoassociation resonance in LiRb. This pair of states displays interesting decay physics that hint at interference-like effects caused by two different decay paths. We observe decay to predominantly X 1 Σ + v = 43, with significant numbers of molecules produced in X 1 Σ + v = 2 -12. This photoassociation resonance also produces ∼300 X 1 Σ + v = 0 J = 0 molecules/second. Finally, we identify a stimulated Raman adiabatic passage transfer pathway from v = 43 to v = 0 that has the potential to produce up to 2 × 10 5 LiRb molecules/second in the X 1 Σ + v = 0 J = 0 state.