Production and state-selective detection of ultracold molecular rubidium (85Rb2) in the singlet ground state and the metastable triplet state are described. Ultracold 85Rb2 molecules are produced via photoassociation followed by radiative decay. State-selective detection of high-ν ground-state and metastable-state molecules is carried out by resonant Two-photon ionization (R2PI) with a pulsed laser. The spectra of both the ground singlet and metastable triplet states are investigated. Spectroscopy of several intermediate excited states, some of which are observed for the first time, is also studied. Mixing between excited singlet and triplet states is observed in both the singlet and triplet spectra. A proposal for producing ν = 0 ground-state molecules by utilizing this singlet-triplet mixing is given. Magnetic trapping and filtering of metastable triplet-state molecules is also described, and a scheme for optical trapping of molecules is proposed.^
We have observed the formation of ground-state
Na2 molecules via the spontaneous decay of excited molecules created by the photoassociation of ultracold atoms. We measure the binding energies of molecules created in three hyperfine components of the lowest singlet and triplet potentials of
Na2 by two different methods. Two of the features are purely triplet a ${}^{3}{\ensuremath{\Sigma}}_{u}^{+}$
(v=15) (quasibound) states that have not been previously observed, while the third is a mixed X ${}^{1}{\ensuremath{\Sigma}}_{g}^{+}--a$ ${}^{3}{\ensuremath{\Sigma}}_{u}^{+}$ state. The molecules are detected with high-resolution cw laser ionization techniques and binding energies are measured to within 10 MHz.