All-optical selective formation of ultracold molecules in the rovibrational ground state

Elena Kuznetsova, Marco Gacesa, Philippe Pellegrini +3 more

Matthias Weidemüller

A. Fioretti, Olivier Dulieu, C. Gabbanini

We perform a comparative study of the formation of ultracold rubidium dimers in their ground state with both 85Rb and 87Rb isotopes. Ultracold rubidium molecules are created through photoassociation of ultracold atoms into rovibrational levels of the 0+u(5S1/2 + 5P1/2) excited state, which interact through resonant coupling (Dion et al 2001 Phys. Rev. Lett. 86 2253) with rovibrational levels of the 0+u(5S1/2 + 5P3/2) excited state. The photoassociated levels decay by spontaneous emission down to rovibrational levels of the X1Σ+g ground state. The resonant coupling is expected to enhance the formation of ultracold molecules in low-lying ground-state levels. By modelling the ionization spectrum of these ultracold molecules, we show that this coupling is larger for 87Rb2 molecules than for 85Rb2 molecules.

Baraa Shammout, Leon Karpa, Silke Ospelkaus +2 more

We study the rovibronic transitions in NaK 2 between its electronic ground state 1 2 A ′ and its second excited state 3 2 A ′ , to identify possible pathways for the creation of ultracold ground-state triatomic molecules. Our methodology relies on the computation of potential energy surfaces and transition dipole moment surfaces for the relevant electronic states using methods. Rovibrational energy levels and wave functions are determined using the discrete variable representation approach. A double-well structure of the potential energy surface is identified for both states, and the related transition strengths between the rovibrational levels are derived. Our calculations show that the formation of ultracold ground-state NaK 2 molecules is expected when starting from an excited electronic state of NaK 2 , which can be created by photoassociation of NaK and K, as observed by optical means by Cao, [].

Olivier Dulieu, Dimitri Borsalino, Andrea Orbán +5 more

Johannes Deiglmayr, A. Grochola, M. Repp +6 more

Ultracold LiCs molecules in the absolute ground state $X^{1}\ensuremath{\Sigma}^{+}$, ${v}^{\ensuremath{'}\ensuremath{'}}=0$, ${J}^{\ensuremath{'}\ensuremath{'}}=0$ are formed via a single photoassociation step starting from laser-cooled atoms. The selective production of ${v}^{\ensuremath{'}\ensuremath{'}}=0$, ${J}^{\ensuremath{'}\ensuremath{'}}=2$ molecules with a 50-fold higher rate is also demonstrated. The rotational and vibrational state of the ground state molecules is determined in a setup combining depletion spectroscopy with resonant-enhanced multiphoton ionization time-of-flight spectroscopy. Using the determined production rate of up to $5\ifmmode\times\else\texttimes\fi{}{10}^{3}\text{ }\text{ }\mathrm{\text{molecules}}/\mathrm{s}$, we describe a simple scheme which can provide large samples of externally and internally cold dipolar molecules.