Low-energy molecular collisions in a permanent magnetic trap
Abstract
Cold, neutral hydroxyl radicals are Stark decelerated and confined within a magnetic trap consisting of two permanent ring magnets. The OH molecules are trapped in the ro-vibrational ground state at a density of 106 cm-3 and temperature of 70 mK. Collisions between the trapped OH sample and supersonic beams of atomic He and molecular D2 are observed and absolute collision cross sections measured. The He--OH and D2--OH center-of-mass collision energies are tuned from 60 cm-1 to 230 cm-1 and 145 cm-1 to 510 cm-1, respectively, yielding evidence of reduced He--OH inelastic cross sections at energies below 84 cm-1, the OH ground rotational level spacing.
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