The decay of the VUV continuum radiation has been measured in the afterglow of a pulsed dc discharge in argon, krypton, and xenon at pressures between 1 and 100 Torr and temperatures between 200 and 400 K. By comparing the results with those obtained in absorption studies, it is inferred that the precursor to the Rast;2excimers is the Rast; (1s5) metastable state. The reaction rates for the formation of excimers Rast;2in threehyphen;body collisions are obtained as a function of temperatureT: The threehyphen;body reaction rate can also be represented in an Arrhenius plot, yielding activation energiesEa(Ar) =minus;0.007 eV,Ea(Kr) =minus;0.020 eV, andEa(Xe) =minus;0.016 eV. The destruction of the Rast;(1s5) state by twohyphen;body collisions results either in the formation of Rast;2excimers or in the transition to the nearby Rast;(1s4) resonance state. Reaction rates for these processes could not be obtained separately, but the resulting total twohyphen;body reaction rate is given in graphical form in the paper.
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