The 2 main techniques which were used to calculate the microscopic electronic structure of localized defects in solids were reviewed. It was recalled that cluster calculations, using the Hartree-Fock method, as well as density functional methods, had been widely used to determine the equilibrium structure of H and H-related complexes in semiconductors. Data on the structure of both acceptor-H and donor-H pairs in Si, obtained by using various methods at various levels of approximation, were considered. Comparisons were made of the calculated vibrational frequencies of H in these passivation complexes. The spin density distribution for bond-centered H or muonium in diamond was investigated. Due to the low masses of the proton and the muon, it was necessary to average the computed hyperfine parameters over a finite extension of the ground-state wave function.

R.Luchsinger, P.F.Meier, N.Paschedag, H.U.Suter, Y.Zhou: Philosophical Transactions of the Royal Society A, 1995, 350[1693], 203-14