The theory of electron diffraction by the void lattice

The theory is given for the electron diffraction by the void lattice in molybdenum, recently observed by Sass and Eyre. The results are analysed to see if this method can give useful new information about the voids and their ordering. The predictions of the positions and intensities of the extra peaks agree with observation. However, the quantitative theory shows that void shapes cannot readily be found from the diffraction data Nor is it easy to get accurate information about void sizes or the nature of the disorder in the void lattice, mainly because of the problems of measuring intensity profiles. The effects of the various forms of lattice disorder are discussed qualitatively.