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A kinetic model for tunneling of the trapped electron e;-from its trap to a scavenger S has been developed. The probability of the transition of e ,-through the three-dimensional potential barrier has been calculated based on the theory of quasistationary states. The transparency of the barrier has been expressed in terms of (1) the distance e;--Sand (2) the energy level in the acceptor molecule. In order to calculate the kinetics of e;-decay. the distribution of e;--S distances, and the energy levels of electrons in the traps have been taken into account. The model has been numerically applied to the decay of electrons trapped in the glassy 8 M NaOH in the presence of NO] used as an electron acceptor. The presented model does not allow one to calculate the density of energy levels in the scavenger accesible to electron. Therefore, this parameter has been chosen to provide the best fit of the theory to the experimental data. The observed time dependence as well as scavenger concentration dependence are in a good agreement with those predicted by the theory.

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The rate constants for scavenging hydrated electrons by Cd2+ in HaO and D2O are the same. In solutions containing 0.025 to 0.4 m CdSCL and 4 M HCIO4 or 4 M DCIO4 (to remove eaq~) the efficiency of scavenging dry electrons e~in D2O is 47% greater than in H2O. In terms of simple competition with dry electron scavenging by Cd2+ and localization, the isotope effect is attributed principally to the latter process which is due to formation of H2O-". The yields of dry electrons accessible to scavenging by Cd2+ (per 100 eV of absorbed energy) are 5.2 in H2O and 4.9 in D2O. The difference between G(Cd+) and -AG(eaq~) at 30 ps is attributed to prompt recombination of e_ and H20+ for small initial charge separations. After relaxation the distribution of eaq" may approximate a spherical annulus, causing a delay in eaq~decay.