Formation of ultracold dipolar molecules in the lowest vibrational levels by photoassociation.

We recently reported the formation of ultracold LiCs molecules in the rovibrational ground state X1sigma+, v" = 0,J" = 0 (J. Deiglmayr et al., Phys. Rev. Lett., 2008, 101, 133004). Here we discuss details of the experimental setup and present a thorough analysis of the photoassociation step including the photoassociation line shape. We predict the distribution of produced ground state molecules using accurate potential energy curves combined with an ab initio dipole transition moment and compare this prediction with experimental ionization spectra. Additionally we improve the value of the dissociation energy for the X1sigma+ state by high resolution spectroscopy of the vibrational ground state.