X-Ray Coloration of Alkali Halides

Abstract

Processes of importance in the coloration of solids by x-radiation are discussed on the basis of Seitz's hypothesis that vacancies are created at jogs on dislocations or at other imperfections. The interaction between $F$ centers and dislocations is calculated, and it is shown that $F$ centers located within about 50A of edge-type dislocations would experience measurable broadening and perhaps shifting of their absorption peaks, in contradiction of experiment. From the available energy in the form of point thermal pulses, it is shown that most vacancies freed from jogs or other sources probably make less than a thousand atomic jumps during x-irradiation at He temperatures and hence are unable to diffuse more than about 100A from their sources.