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 r equire the presence of Mu(T)(-). We determine the Mu(T)(-) to Mu(T)(0) ioni zation energy to be 0.56+/-0.03 eV for silicon, considerably higher than th e 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/+) therm odynamic level correlates well with results for monatomic hydrogen, but the Mu(-/0) level is estimated to be shallower than that claimed for H(-/0). T he muonium data show a complicated set of transitions active during the muo n Lifetime, and involving four separate muonium states. Similar rapid trans itions should be considered when interpreting data on isolated hydrogen cen ters. [S0163-1829(99)11107-X].