The alkaline dimers and their cations have been studied previously with classical spectroscopy techniques and photoassociation of cold atoms.One of the goals of this study was to obtain molecular data appropriate to the interpretation of collisionnal processes. We did a systematic study of molecular alkaline ions while assessing the precision of the results depending on the hypothesis which had been chosen. We compared our résults obtained with a pseudopotential method with those obtained with a potential method for the heavy ions Rb2+, Cs2+ and RbCs+.The rates of photoassociation of mixed alkali dimers, as well as the rates of formation of cold molecules in the ground stats, were calculated using a perturbative approach for which the wavefunctions are exactly detemined.These rates have the same magnitude for all the heteronuclear dimers contained Rb and Cs atoms.The rates of cold molecules formation are similar to those mesured and computed for Cs2 molecules. We studied the specific case of photoassociation in two states coupled by a spin-orbit interaction who emphasizes the role of the resonant coupling in the formation of stable cold molecules in levels weakly excited.
