Affiliation: | (1) Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany;(2) Laboratoire Aimé Cotton, CNRS, Campus dOrsay, 91405 Orsay Cedex, France;(3) Fakultät für Physik, Universität Bielefeld, 33615 Bielefeld, Germany |
Abstract: | Cold alkali diatomic molecules (LiCs, NaCs) in the lowest vibrational state of the electronic triplet ground state are formed on superfluid helium nanodroplets. Using photoionization detection the excitation spectra of the transitions are recorded. The splitting of the vibrational structure in the LiCs spectrum, not observed in the NaCs spectrum, is interpreted in terms of molecular fine structure. The spectra are well reproduced by a model based on quantum chemistry potential curves including spin-orbit coupling, in combination with an asymmetric line shape function to account for cluster-induced broadening. Our refined potential curves provide important input data for the photoassociation of ultracold dipolar alkali molecules from atomic quantum gases.Received: 1 July 2004, Published online: 26 October 2004PACS: 36.40.Mr Spectroscopy and geometrical structure of clusters - 34.50.Gb Electronic excitation and ionization of molecules; intermediate molecular states (including lifetimes, state mixing, etc.) - 33.20.-t Molecular spectra |