CXLVI. The anisotropic absorption of the visible bands in irradiated α-quartz

Abstract

Measurements have been made, using polarized light, of the anisotropy of the visible absorption of centres induced in quartz by x-ray, gamma and neutron irradiation. The ratio of the integrated absorption when the electric vector is parallel to the c-axis to that when it is perpendicular, is 1 ·5. An experiment is described which suggests that the optical absorption is associated with substitutional aluminium impurity. It is shown that a value of 1·3 would be expected from the O'Brien and Pryce model of the magnetic resonance centre which is induced under similar conditions.