Muonium in ice

Muonium has been studied in single crystals of H2O and D2O. Two-frequency precession in low transverse fields and a single zero-field oscillation indicate a small anisotropy of axial symmetry in the muonium hyperfine interaction. The anisotropy is shown to be the cause of the hitherto unexplained temperature independent contribution to muonium spin relaxation in polycrystalline samples. Relaxation rates for 99 K-263 K are reported for muonium in a single crystal of H2O. Relaxation is attributed to electron-nuclear dipolar coupling of muonium to lattice protons, modulated by translational diffusion of muonium along c-axis channels of the ice lattice. A simple model for H and Mu diffusion in ice is investigated. (Auth.)