Reactions of Excited Inorganic Ions in Crystals

On illuminating KC1 crystals containing additives of In+ ions in concentrations of 10-4 to 10-2 M, electron transfer from the excited ion of indium to the indium ion in the ground state was observed [37] 

At low temperatures (7-100 K), the probability, W, of this reaction has been found [37] to be independent of temperature while at T 100 K, the reaction rate was observed to increase with increasing temperature. The presence of a temperature-independent region for the dependence of W on T and the unusually sharp dependence of the probability of photoionization of In + centres on their concentration (i.e. on the distance between them) have been acounted for by electron tunneling from In 1 to In +. The probability of tunneling has been found to decrease by e times at a distance of one lattice constant. With the exponential dependence of W on the distance R between the In+ and In+ particles of the form (1), such a decrease of W with increasing R corresponds to the value of ac = 12.6 A. Such an unusually high value of the parameter ae for the reaction in 

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