Hyperfine properties of bond-center muonium and hydrogen in diamond

The bond-center (BC) hydrogen/muonium defect is of considerable interest both as a model for the theoretical description of defects in semiconductors, and because of its possible role in affecting the opto-electronic properties of polycrystalline silicon and diamond. Its identification requires a reliable calculation of its hyperfine couplings (HFCs) both in the bulk and in strained bonds that occur at grain boundary sites. Using a novel multiconfigurational perturbative approach we have calculated the HFCs of BC muonium/hydrooen in diamond. To our knowledge the method provides the best compromise between accuracy and computational efficiency. Our results for the bulk BC muonium defect are in very good agreement with experiment. As an application of this method, we have obtained the HFCs for hydrogen in strained C-C bonds. (C) 1996 American Institute of Physics.