It was recalled that the bond-center H/muonium defect was of interest as a model for the theoretical description of defects in semiconductors, as well as with regard to its possible role in influencing the opto-electronic properties of polycrystalline Si and diamond. Its identification required the reliable calculation of its hyperfine coupling in the bulk, and in strained bonds at grain boundary sites. A new multi-configurational perturbation approach was used to calculate the hyperfine coupling of bond-center muonium/H in diamond. The method was thought to provide the best compromise between accuracy and computational efficiency. The results for the bulk muonium defect were in very good agreement with experiment. As an application of the method, the hyperfine couplings were deduced for H in strained C-C bonds.

S.Chawla, R.P.Messmer: Applied Physics Letters, 1996, 69[21], 3251-3