ELECTRON ION RECOMBINATION IN DENSE GASEOUS XE/

The electron mobility it, and the electron/ion recombination rate cons tant k(r) in dense gaseous xenon at 0.9, 1.6, and 5.0 x 10(21) atom cm (-3), near the critical density of 5.1 x 10(21) atom cm(-3) at 292 K, have been measured as a function of an external electric field using a pulse-radiolysis d,c.-conductivity method. Although the values of mu( e) are much smaller than those for previous measurements in CH4, Ar, a nd Kr, k(r) has been found to be well below the diffusion-controlled r ecombination rate constant indicated by the reduced Debye equation. By comparison with theories, possible reaction-control stages involving the relaxation processes of excess energy, which emerges upon recombin ation of ion clusters with electrons via resonant capture, and their d ependence on gaseous media are discussed.