Photo-dissociation of Cold MgH+ ions -: Towards rotational temperature measurements and controlled dissociation

Molecular ions sympathetically cooled into a Coulomb crystal by laser cooled atomic ions represent,in many ways an ideal target for molecular physics studies due to achievable low translational temperatures (similar to10 mK) and strong spatial localization (similar to1 mum). In particular, in experiments with focused laser beams, both these features can be extremely useful. Here, we present results from experiments on photo-dissociation of MgH+ ions in Coulomb crystals, and discuss possible avenues for using such processes for rotational temperature measurements as well as for manipulating the branching ratio of the dissociation channels Mg+H+ and Mg++H through intensity and frequency control of the laser beams involved.