Ionization spectroscopy of ultracold rubidium dimers through the (1) 3Pg state

A. Fioretti, Nadia Bouloufa-Maafa, C. Gabbanini +8 more

A. Fioretti, Nadia Bouloufa-Maafa, C. Gabbanini +8 more

Edward E. Eyler

Christoph Strauß

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.

Andreas Przystawik, Paul Radcliffe, Sebastian Göde +2 more

Silver dimers embedded in ultracold helium nanodroplets are ionized by two-photon excitation via a strong resonance which extends from 3.85 eV up to 4.1 eV. The corresponding photoelectron spectra reveal that the ionization threshold is shifted by more than 1.4 eV towards lower values when compared to the gas phase. This gives strong evidence that weakly bound dimers in the lowest lying triplet state are present, thus enabling convenient spectroscopy of the triplet Ag 2 . A comparison with predictions from theory allows an assignment of the structure in the spectra. The successful identification of triplet silver dimers embedded in helium droplets shows exemplarily that the formation of such weakly bound systems is not restricted to surface locations as with the alkalis, but represents a general feature of the ultracold helium droplet environment.