Electron spin relaxation in solid metal-ammonia solutions. Evidence for highly mobile electron pairs near the metal-non-metal transition

The existence of a very narrow, homogeneously broadened electron spin resonance signal in frozen metal-ammonia solutions requires rapid modulation of electron-nuclear hyperfine interactions. Previously proposed models of unpaired electron motion in fluid solutions depend on viscous motion and so are not applicable to the solid state. The mobile electron pair model proposed by Catterall and Mott (1969) to describe the metal-non-metal transition in fluid solutions provides a natural explanation for the high mobility in the solid state.