New Methods in Mössbauer and X-Ray Crystallography

Abstract

This thesis describes the development of three new methods for studying the site positions of specific elements in a crystal lattice independently of their surroundings, in situations for which existing methods have proved to be inadequate. The first two of these use Mössbauer spectroscopic methods; one is based on measuring the peak area ratio of the absorption lines in the Mössbauer spectrum, and the other on Mössbauer resonance diffraction effects. The third method, applicable to a much wider range of elements, uses the anomalous scattering effects of X-rays. The potential of this latter method is shown to be greatly enhanced by the use of the new energy dispersive X-ray diffraction procedures, incorporating high resolution solid state detectors. As examples of the applications of these methods, the iron distribution in the minerals, olivine, cordierite and beryl have been studied. Also the manganese distribution in a tourmaline sample has been determined using the energy dispersive X-ray method.