Short-range photoassociation of LiRb

Abstract

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...

Ultracold molecule assembly with photonic crystals

“…In the present case, due to initial ultracold temperature following laser cooling, free 87 Rb atoms will collide in the pure s-wave scattering regime through the a u 3 S + molecular potential, which is properly described by the Hund's case b. The initial state thus processes even parity [39], N=0 rotational quantum number and J=1 total angular momentum quantum number. The PA-excited molecular state in 1 g 3 P , on the other hand, is better described in the Hund's case c with the triad J M ¢W¢ ¢ñ | .…”

“…As an example, we consider 87 Rb 2 diatomic molecules, whose PA spectroscopy and TDMs are known in the literature [22,36,37], although we emphasize that this scheme can be extended to other bi-alkali molecules presenting short-range PA pathways [38][39][40]. Specifically, we calculate the vibrational states of 87 Rb 2 associated with the relevant potential energy curves taken from [36] using the Numerov method 3 .…”

“…Here, W¢ stands for the projection of the angular momentum in the molecular axis with M¢ its projection into the lab frame. Considering electric dipole selection rules [46][47][48], parity selection rule (  ) [39,46,47], and the relevant TDM (appendix A), J 1, 2 ¢ = states can be excited using PA.…”

Continuous production of rovibronic-ground-state RbCs molecules via short-range photoassociation to thebΠ13–cΣ1+Shimasaki1, Kim2, Zhu3 et al. 2018Phys. Rev. A120100View full textAdd to dashboardCite

“…Over the past several years, a series of studies showed that short-range PA is generally possible for bi-alkali molecules: short-range PA has been demonstrated for NaCs [9], Rb 2 [10,11], LiCs [12], RbCs [13][14][15], and LiRb [16,17]. Furthermore, production of rovibronic groundstate has been verified for LiCs [12], RbCs [14,15], and LiRb [17].…”

Photoassociation reaction of OH molecules through reverse ladder transition

“…For the long-range PA, the collision atoms with low collision energy mainly form alkali-metal molecules, such as Rb 2 , Cs 2 , Li 2 , Na 2 , LiRb, RbCs, NaCs, and LiCs [9][10][11][12] . The short-range PA for alkali-metal molecules also has been studied both theoretically and experimentally [13][14][15][16][17] . The short-range PA with high energy collision has been proposed theoretically and its products include OH, HBr, HF, HI, and NaH [8,18,19] .…”