Magnetic trapping of SH radicals

Data showing magnetic trapping of SH radicals, produced via a process we call photostop. H2S in a skimmed, supersonic molecular beam was photodissociated to produce SH inside a 330 mK deep static magnetic trap. The molecular beam speed was controlled by the mixing ratio of H2S in Kr to match the recoil velocity of the SH photofragments such that some SH radicals were produced with near-zero laboratory-frame velocity. The density of SH radicals in the 2Π3/2, v = 0, J = 3/2 state was followed by (2+1) REMPI over seven orders of magnitude of signal intensity. 5 ms after photodissociation, SH radicals moving faster than the capture velocity of 13 m/s left the trap. The 1/e trap lifetime of the remaining SH radicals was 40 ± 10 ms at an estimated density of 5×104 molecules/cm3. Photostop offers a simple and direct way to accumulate absolute ground state molecules in a variety of traps.