Interaction of NH(X3Σ-) with Rb and Cs atoms:: similarities and differences from an highly correlated ab initio study

The interactions of Rubidium and Cesium atoms with the NH radical at its equilibrium geometry are investigated over several interpartner distances and for a variety of angular orientations of the atoms with respect to the intermolecular bond. Several electronic states are computed at the CASSCF level and the lowest four are analysed in greater detail at the MRCI level in order to finally obtain orientational potential energy surfaces. The evaluation of the involved Franck-Condon factors reveals the possibility of photoassociation mechanisms into bound states of the two complex triatomics and further suggests stable complex configurations in the lowest quartet states from DVR calculations of the J = 0 relevant bound states. The work above exemplifies the recent interests of the theory group in Rome on ultracold dynamics and interaction processes which are also briefly reviewed in the introduction.