Infrared Absorption in Proton-Irradiated Solid Deuterium

The infrared absorption spectrum of solid D2 at 4.2 K has been studied with the sample irradiated by a 15-MeV proton beam. Three beam-induced spectral features have been observed. Comparison of these features with those previously seen in a sample doped with tritium conclusively establishes the presence and indicates the nature of a radiation-induced absorption process. After turning off the proton beam, these features persist for times of the order of hours; they can be quenched by heating the sample to ∼ 11 K.