THEORY OF TRAPPED-HOLE CENTERS IN RARE-GAS SOLIDS

Experimental evidence suggests that self-trapping of holes occurs in rare-gas solids. Formation of an intrinsic diatomic center, similar to the Vk center, is investigated as a possible mechanism. The energy of trapping a valence-band hole is discussed on the basis of a simple model for the rare-gas hole center. A method of calculating the relaxation and polarization energies is developed, appropriate parameters for the model estimated, and the method applied to solid argon, krypton, and xenon to determine the degree of relaxation and the contributions to the trapping energy. The results suggest stable trapped-hole centers at 0°K associated with only small lattice relaxations. The internal molecular binding of the center is found to be the overwhelming factor determining its configuration on this model.