Reported here is the first observation of an alpha-Muonium-substituted
methyl radical. The key to the success of this experiment was the use
of a more stable precursor, trimethylsilyldiazomethane, iii lieu of t
he prototypical diazomethane. The radical, .CHMuSi(CH3)3 was observed
by TF-muSR, with A(mu)=187.6(2) MHz. This result is compared to litera
ture values for the proton analogue and the isotope effect is discusse
d.