Plastic-strain induced peaks in the spectrum of F-light-stimulated photoconductivity in colored NaCl crystals

An electronic level that may be ascribed to electrons captured by dislocations has been detected and investigated in NaCl single crystals using the photoconductivity technique. In essence, exposure of a crystal to infrared radiation gives rise to an increase in photoabsorption and infrared photoconductivity stimulated by light exciting F-centers (F-light). It was found that plastically deformed crystals show up an additional band in the spectrum of infrared photoconductivity stimulated by F-light. This band corresponds to photon energies in the range of 0.65–1.11 eV and contains two peaks, at 0.74 and 0.88 eV. The position of the former peak is consistent with the data on IR quenching of the photoplastic effect, which is generally ascribed to the excitation of the dislocation electronic level.