Rayleigh scattering of Moessbauer radiation from plastic crystals

A survey is given of some results on the Rayleigh scattering of Moessbauer radiation from plastic crystals in polycrystalline form. In each case the elastic component in the scattered radiation shows a more or less abrupt decrease in value on warming through each phase transition at which molecular motion increases. The possibility of obtaining detailed information on the nature of molecular rotation in the plastic crystal phase is discussed