Dynamics of negative muonium in n-type silicon

Temperature-dependent diamagnetic amplitudes from radio-frequency muon spin-resonance data on two moderately to heavily doped n-type silicon samples require the presence of Mu(T)(-). We determine the Mu(T)(-) to Mu(T)(0) ionization energy to be 0.56+/-0.03 eV for silicon, considerably higher than the Mu(BC)(0) to Mu(BC)+ ionization energy of 0.21 +/- 0.01 eV. Thus muonium will be a negative-ii impurity only if the energy difference between the Mu(T)(0) and Mu(BC)(0) configurations is less than 0.35 eV. The Mu(O/+) thermodynamic level correlates well with results for monatomic hydrogen, but the Mu(-/0) level is estimated to be shallower than that claimed for H(-/0). The muonium data show a complicated set of transitions active during the muon Lifetime, and involving four separate muonium states. Similar rapid transitions should be considered when interpreting data on isolated hydrogen centers. [S0163-1829(99)11107-X].