Isolated H and muonium in crystalline material were studied by using the path-integral Monte Carlo method which involved a parametrized Si-H interaction that had been deduced from earlier ab initio calculations. The H and D were found to be stable at the bond-center site, but this position was metastable in the case of muonium. The average values of the kinetic and potential energies of the defects were compared with those that were expected for H-like impurities within an harmonic approximation. Backward relaxation of the Si-atom nearest-neighbors of the impurity was found to depend upon the impurity mass. Greater host-atom relaxation occurred for higher impurity masses.
C.P.Herrero, R.RamÃrez: Journal of Physics - Condensed Matter, 1996, 8[43], 8309-20