Electron Spin Relaxation in Metal-Ammonia Solutions

Abstract

The electron spin resonance relaxation times (T1 and T2) for solutions of lithium, sodium or potassium in liquid ammonia have been measured by transient methods for a resonant frequency of 9340 Mc/s over the temperature range -75 °c to 80 °c. T1 and T2 are equal except for potassium for which T2 is shorter than T1 by an almost constant amount over the whole temperature range. From the equality of T1 and T2 an upper limit on the correlation time of the electron spin interaction with 14N nuclei of 3.5 × 10-12 sec at -33.3 °c is established. An estimate is made of the effective number of 14N nuclei in interaction with the electron spin which excludes the `cavity' model for these solutions. For the dilute solutions of lithium, ζT1, where ζ is the shear viscosity of pure liquid ammonia, is independent of temperature whereas for sodium ζT1/T is about constant.