Multielement NMR Studies of the Liquid-Liquid Phase Separation and the Metal-to-Nonmetal Transition in Fluid Lithium- and Sodium-Ammonia Solutions

H-1, Li-7, N-14 and Na-23 high resolution nuclear magnetic resonance (NMR) measurements are reported for fluid solutions of lithium and sodium in anhydrous liquid ammonia across the metal-to-nonmetal transition (MNM transition), paying particular attention to the phenomenon of liquid liquid phase separation which occurs in the composition/temperature region close to the MNM transition. Our results are discussed in terms of the electronic structure of fluid metal ammonia solutions at low temperatures (ca. 240 K). We find that the electronic phase transition to the metallic state in these solutions, especially at temperatures close to the liquid liquid critical consolute temperature, occurs from a nonmetallic, electrolytic solution containing a predominance of electron spin-paired, (diamagnetic) charged bosonic states. The possible implications of these observations to the nature of the liquid liquid phase separation are discussed, both from the views of N. F. Mott, regarding the MNM transition in sodium ammonia solutions, and those of R. A. Ogg, regarding the possibility of high-temperature superconductivity in these solutions. Similarities between the electronic structure of metal ammonia solutions and the high-temperature cuprate superconductors are also briefly emphasized.