Energy States for Nuclear Motion

We have seen, by means of elementary theoretical considerations, that it is possible to deduce the activation energies for displacement of atoms or ions in a lattice from observations of the temperature dependence of diffusion and electrolytic conduction. 

One application of radioactive tracer techniques of considerable importance in solid state structural problems is the emanation method due to Hahn (21). The method has been employed widely and has been developed recently as a sensitive, quantitative method by Gregory (22), who has employed it for the investigation of structural changes and for the extraction of diffusion data. The procedure in outline is as follows A convenient amount of a radioactive element which decays to an isotope of radon (e.g., radiothorium) is ccprecipitated 

One of the major difiiculties of this work is to establish that the current carriers are ions. Evidence must be drawn from other experiments to establish this (e.g., Hall coefficient, polarization phenomena, e.in.f. of suitable cells, etc.). Table 4 gives a selection of solids for which the type of conduction has been determined by these methods (25). 

3 Structural Consequences of Presoice of Defects A static property of a crystal, such as its structure, can 

Observations by X-ray methods are usually restricted to powder samples, from which one can obtain evidence of 

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