Impact of electric fields on highly excited rovibrational states of polar dimers

We study the effect of a strong static homogeneous electric field on the highly excited rovibrational levels of the 7Li133Cs dimer in its electronic ground state. Our full rovibrational investigation of the system includes the interaction with the field due to the permanent electric dipole moment and the polarizability of the molecule. We explore the evolution of the states next to the dissociation threshold as the field strength is increased. The rotational and vibrational dynamics are influenced by the field; effects such as orientation, angular motion hybridization and squeezing of the vibrational motion are demonstrated and analyzed. The field also induces avoided crossings causing a strong mixing of the electrically dressed rovibrational states. Importantly, we show how some of these highly excited levels can be shifted to the continuum as the field strength is increased, and conversely how two atoms in the continuum can be brought into a bound state by lowering the electric field strength.Financial support by the Spanish projects FIS2008-02380 (MEC) and FQM-0207, FQM-481 and P06-FQM-01735 (Junta de Andalucía) is gratefully appreciated. This work was partially supported by the National Science Foundation through a grant for the Institute for Theoretical Atomic, Molecular and Optical Physics at Harvard University and Smithsonian Astrophysical Observatory. Financial support by the Heidelberg Graduate School of Fundamental Physics in the framework of a travel grant for RGF is gratefully acknowledged. We thank Michael Mayle for his help with respect to technical aspects of this work