Conduction electron spin resonance in liquid and solid sodium

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Abstract
The spin lattice relaxation time has been measured in liquid and solid sodium as a function of temperature from 293°k to 453°k. The relaxation times observed have been explained using a theory by Helman based upon an OPW dynamical treatment of the liquid state. This represents the first case in which the theory and experimental result have been compared. The calculated value of the relaxation time in liquid sodium at 373°k is 3·4 × 10−9 sec whilst the experimental value is 5·6 × 10−9 sec. The theory also explains the origin of the difference in behaviour of the resistivity and spin relaxation in the liquid and satisfactorily predicts the observed temperature dependence of the spin relaxation time. Extension of the theory to the solid is found to predict the correct temperature dependence to below 40°k. The g shift of conduction electrons in solid sodium has been measured to higher accuracy than previously and is found to be 9·7 ± 0·3 × 10−4. No change in g shift was observed on melting. An attempt has been made to detect changes in the spin susceptibility and Fermi energy on melting. To within the accuracy of the experiment (15%) no change in either of these parameters was observed.