Electron Spin Resonance Studies of Concentrated Alkali Metal-Ammonia Solutions

Electron spin resonance spectra are obtained for sodium and cesium metal-armnonia solutions in the concentration range 1.0 molal to saturation. The asymmetric spectra are interpreted on the basis of existing theories for magnetic resonance in metallic conductors. The transverse relaxation time T2 decreases with increasing concentration until it reaches a limiting value close to that observed for the pure metal. Electron spin resonance spectra are obtained for concentrated sodium metal-ammonia solutions containing dissolved cesium halide salts. T2 and g decrease with sodium metal concentration and are anion independent. The addition of the cesium cation causes a decrease in T2 which is independent of cesium concentration above 0.10 molal salt. These results are taken as evidence for the formation of a lattice structure in concentrated solutions.