ggr;hyphen;irradiated 3hyphen;methylpentane (3MP) and solutions of biphenyl (phgr;) have been examined at minus;196deg; at doses of 1 to 26times;1018eV mlminus;1. The halfhyphen;life for decay of the trapped electron (eminus;) in 3MP is independent of dose fort1 h and the rate is approximately second order fort1 h. This behavior, as well as very efficient formation of phgr;minus;at small phgr;, requires electron track lengths of sim;10minus;4cm. The 100 eV yield of (eminus;) shortly after ggr; irradiation is sim;0.9, in terms of the measured extinction coefficient egr;(eminus;)cong;3.0times;104liter moleminus;1middot;cmminus;1at 2.3times;1018eV mlminus;1, but only 60 as great at 10hyphen;fold greater dose. At 0.04 phgr;, the rate of (eminus;) decay is much faster and approximates first order. The ratio of reaction cross sections of (eminus;) with positive holes and phgr; is sim;120. Addition of 2 2hyphen;methylpenteneminus;1 as positive hole trap increases the yield of (eminus;) and decreases the rate of decay, which becomes second order throughout. Recombination luminescence intensity from TMPD att1 h decays at the same rate following uv and ggr; excitation. The evidence for randomization of relatively large yields of ion pairs and very long track lengths, as well as trapping and escape, may require a new theoretical framework.
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