Fluorescence and Thermoluminescence of Ice

Experiments on the x-ray excited fluorescence and thermoluminescence of pure ice and ice containing certain additives are described. The luminescent spectra are explained by a model in which the primary process is the radiative capture of electrons by impurity cations. The first-order buildup of fluorescence and temperature dependence of luminous intensity are interpreted by the breakdown and formation of the dipole sheath surrounding the dissolved ions. From this viewpoint, the activation energy for rotation of a sheath ice dipole from the normal lattice position to the aligned configuration is calculated to be 0.07 ev. The principal trap depth determined from the glow curve is 0.32 ev, a correction for the luminous efficiency being incorporated in the calculation; the corresponding s value is 2×108 sec—1. Possible mechanisms for the first-order thermoluminescence are given.