Interaction of slow positrons with H− ions in alkali metal hydrides

The probabilities of the fundamental interaction processes of slow positrons (in the energy interval from 0.025 to 5.46 eV) with H^– ions were calculated on the basis of the self-consistent field method. Curves of the angular correlation of gamma-quanta during two-photon annihilation of positrons moving in the field of H^– ions with energies of 0.025, 0.546, 1.365, 2.73, and 5.46 eV were obtained. Comparison of the probabilities of annihilation and radiation capture by H^– ions with the probabilities of processes occurring with thermalized positrons makes it possible to establish more clearly the annihilation mechanism of slow positrons in alkali metal hydrides.