Excess electrons in the lithium-methylamine system studied by electron spin resonance at 200 MHz

The electron spin resonance of lithium-methylamine solutions has been measured at 200 MHz over a wide concentration range of the dissolved metal. The transverse relaxation times of the excess electrons deduced from the observed spectral widths show two different regions: the lower metal concentration region where the relaxation times increase with metal concentration and temperature and the higher metal concentration region where the trend is opposite. It is concluded that in the former region the hyperfine interaction of the excess electron spins with 14 N nuclei is dominant, while in the latter region the spin-orbit interaction to the metal ions is dominant. The crossover occurs at a metal concentration lower than the bulk metal-nonmetal transition located at ca. 15 mol% metal