The self-consistent electron structures of the perfect Si and GaAs lattices are calculated by the linear-muffin-tin-orbital (LMTO) band-structure method within the atomic-sphere approximation (ASA). Monovacancies in different charge states are treated by the self-consistent LMTO-ASA Green's-function method. The corresponding positron states are determined by the same methods and positron annihilation characteristics are calculated. The results are compared with recent experiments.
 

Physical Review B, 34 2695-705, 1986.