Direct evidence for muonium radicals in water solutions

The precession frequencies of muonium in a molecular radical state have been observed by μSR technique in diluted solutions of 2,6-dihydroxy-5-methyl-pyrimidine (thymine) in water. The conditions for the observation of the radicals are discussed in terms of the interdependent roles played by the chemical reaction time for muonium and by the external magnetic field. A comparison with the known ESR data on solid thymine confirms that the observed product of the muonium's reaction is an adduct radical with an hyperfine interaction reduced to 7% ± 1% of the muonium value