Resolved nuclear hyperfine structure of a muonated free radical using level-crossing spectroscopy

Abstract

The hyperfine (hf) couplings of all the $^{19}\mathrm{F}$ nuclei in the muonated free radical\ensuremath{\cdot}${\mathrm{C}}_{6}$${\mathrm{F}}_{6}$-Mu have been measured using a level-crossing-resonance technique. Slow damped oscillations of the muon spin polarization in a large longitudinal magnetic field or frequency splittings in transverse field occur at particular field values at which there is a near degeneracy in the muon fluorine hf levels. Thus a resonantlike effect is observed in the muon-spin-rotation spectrum as a function of magnetic field. The positions of such level-crossing resonances allow an accurate determination of the magnitude and sign of the fluorine hf parameters relative to the muon hf parameter.