Quenching efficiciency of "hot" polar molecules by 4He buffer at ultralow energies: quantum results for MgH and LiH rotations

Rotationally superelastic collisions are computed from quantum dynamical calculations for the two title systems, down to the very low collision energies of interest in cold trap experiments. The results are obtained via ab initio interaction potentials, the one for the MgH-He system being given here for the first time and discussed in details in the present paper. The calculations show marked differences in behaviour for both cooling efficiency rates at vanishing temperatures and individual cross sections between levels, and their origin is related to target structural properties and with specific features of the two potentials. © 2008 EDP Sciences/Società Italiana di Fisica/Springer-Verlag.