Cold atoms and molecules from fragmentation of decelerated SO2

Using the example of the SO2 molecule, we will discuss photodissociation at threshold as a possibility for producing cold molecules or atoms. The fragments SO and O have low excess energy and are free radicals with high interest for applications like cold chemistry. The threshold behavior is tunable by external fields and shows great similarity to Feshbach resonance studies in cold atom collisions. To take full advantage of the cold fragmentation, it is necessary to dissociate within a cold sample of molecules. In our initial experiments we have demonstrated substantial Stark deceleration of SO2.