Multielement NMR Studies of the Liquid鈥揕iquid Phase Separation and the Metal-to-Nonmetal Transition in Fluid Lithium鈥?and Sodium鈥揂mmonia Solutions

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• 作者：Matthew T. J. H. Lodge ; P. Cullen ; Nicholas H. Rees ; Neil Spencer ; Kiminori Maeda ; Jeffrey R. Harmer ; Martin O. Jones ; Peter P. Edwards
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：October 24, 2013
• 年：2013
• 卷：117
• 期：42
• 页码：13322-13334
• 全文大小：610K
• 年卷期：v.117,no.42(October 24, 2013)
• ISSN：1520-5207

文摘

¹H, ⁷Li, ¹⁴N, and ²³Na 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鈥搇iquid 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鈥揳mmonia 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鈥搇iquid 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鈥搇iquid phase separation are discussed, both from the views of N. F. Mott, regarding the MNM transition in sodium鈥揳mmonia solutions, and those of R. A. Ogg, regarding the possibility of high-temperature superconductivity in these solutions. Similarities between the electronic structure of metal鈥揳mmonia solutions and the high-temperature cuprate superconductors are also briefly emphasized.