The optical absorption spectra of trapped electrons were observed in γ-irradiated ethylene glycol–water, methanol, 10M NaOH, and MTHF at 4°K. The prominent infrared absorption bands were observed in ethylene glycol–water and ethanol glasses, while the bands in methanol, 10M NaOH, and MTHF glasses were similar in shape, slightly red shifted, to the bands for the radiolysis at 77°K. When the glasses were warmed to 77°K, the bands changed irreversibly into those for the radiolysis at 77°K, reducing the absorption intensity. The spectral changes at the intermediate temperatures between 4°K and 77°K were recorded for ethylene glycol–water and methanol cases. The results are interpreted by the molecular reorientation model proposed in the previous paper [T. Higashimura, M. Noda, T. Warashina, and H. Yoshida, J. Chem. Phys. 53, 1152 (1970)].

Thermoluminescence dosimetry is a powerful tool for obtaining the distribution of gamma dose, heretofore unknown, from the atomic bombs dropped on Hiroshima and Nagasaki. Roof tiles irradiated by the bombs show intense thermoluminescence, and the radiation dose for samples irradiated below 100 r by the bomb can be measured by this method.

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Optical absorption and ESR measurements were carried out on et− produced in ethanol at 4°K. The same et− yield for γ radiolysis at 4 and 77°K indicates that electrons are stabilized in pre-existing traps at 4°K where molecular dipoles remain unrelaxed. et− prior to solvation can be classified into two groups. One with λmax = 1500 nm, W1/2= 4 × 103 cm−1 and Δ Hpp = 5.5 ± 0.5 G is easily photobleached by the infrared light. The other with broad absorption band in the visible and Δ Hpp = 13.5 ± 1.5 G is not photobleached by the infrared light. The successive shift of the absorption spectrum to the higher energy side on warming is interpreted by the molecular reorientation mechanism. et− decay is observed during the solvation process, depending on time required for the solvation. The blue shift of the absorption spectrum on reducing the temperature is attributed to contraction of electron traps.