We have investigated phosphorescence, thermoluminescence, and photostimulated luminescence in manganese activated zinc silicate phosphors, both with and without arsenic doping. Both phosphorescence and photostimulated luminescence intensities are found to decay as the reciprocal of the time, a result which requires a different interpretation from that given by the usual model of electron release from a distribution of trap levels. To account for these results we propose a new model based on the radiative recombination of electrons and holes through tunneling from shallow traps or from excited states of the deeper traps. A simple expression is derived which describes the decay of both types of luminescence in phosphors under very general conditions for which tunneling is the dominant recombination mechanism. Excellent agreement between theory and experiment is found.

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Results from recent calculations of the neutron-scattering cross section for energy transfer up to 1 eV have led to a new picture of spin waves in nickel, one in which spin waves exist out to the zone boundary. Our prediction of the dispersion curve and peak widths is in general agreement with data from subsequent neutron-scattering experiments. This provides additional evidence that the "average" spin-splitting energy for nickel is in the 300-to 400-meV range.

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