Jan Schnabel et. al. PHYSICAL REVIEW A 103, 022820 (2021)

We theoretically investigate the prospects for photoassociation (PA) of Rb₃ , in particular at close range. We provide an overview of accessible states and possible transitions. The major focus is placed on the calculation of equilibrium structures, the survey of spin-orbit effects, and the investigation of transition dipole moments. Furthermore we discuss Franck-Condon overlaps and special aspects of trimers including the (pseudo) Jahn-Teller effect and the resulting topology of adiabatic potential-energy surfaces. With this we identify concrete and suitable PA transitions to potentially produce long-lived trimer bound states. Calculations are performed using the multireference configuration-interaction method together with a large-core effective core potential and a core-polarization potential with a large uncontracted even-tempered basis set.

Tobias Kampschulte and Johannes Hecker Denschlag New J. Phys. 20 (2018) 123015

Ultracold ground-state molecules can be formed from ultracold atoms via photoassociation followed by a spontaneous emission process. Typically, the molecular products are distributed over a range of final states. Here, we propose to use an optical cavity with high cooperativity to selectively enhance the population of a pre-determined final state by controlling the spontaneous emission. During this process, a photon will be emitted into the cavity mode. Detection of this photon heralds a single reaction. We discuss the efficiency and the dynamics of cavity-assisted molecule formation in the frame of realistic parameters that can be achieved in current ultracold-atom setups. In particular, we consider the production of Rb₂ molecules in the a³Σ_u triplet ground state. Moreover, when working with more than two atoms in the cavity, collective enhancement effects in chemistry should be observable.

Deiß et. al. PRL 113, 233004 (2014) and Deiß et. al. Physik in unserer Zeit 2/2015 pages 60-61 (2015)

We have controlled the alignment of the molecular axis of nonpolar Rb₂ molecules by preparing specific, precisely defined rotational quantum states. The moelcules were trapped in a 3D optical lattice and their alignment was probed by measuring the molecular polarizabilities for all three directions of space. For a measurement of the polarizability of triplet Rb₂ molecules in their rovibrational ground state, see also: Deiß New. J. Phys. 17, 065019 (2015)

Drews et. al. Nat. Commun. 8, 14854 (2017)

We have carried out controlled collisions of Rb₂ molecules. These molecules were prepared in a 3D optical lattice with no more than a single molecule per lattice site. Afterwards one of the lattice beams was switched off such that molecules could collide within an array of quasi-1D potential tubes. We have measured the decay rates for specific molecular states. Interestingly we found similar decay rates for the triplet rovibrational ground state and rotationally or vibrationally excited states.

Deiß et. al. New J. Phys. 17, 083032 (2015) and Drews et. al. Phys. Rev. A 95, 062507 (2017)

We have investigated the level structure of different electronic states of the Rb₂ molecule, typically achieving a resolution of the vibrational, rotational, hyperfine, and magnetic quantum number degrees of freedom. For this we used different techniques such as photoassociation, photoexcitation and dark state spectroscopy.