Synchrotron radiation time spectra affected by diffusion: theory

The general theory and a qualitative picture of time spectra in nuclear resonant scattering of synchrotron radiation in the presence of diffusive motion of atoms are presented. The coherent channel of the nuclear exciton decay with emission of a γ quantum in a primary direction and the incoherent channel are considered. The theory is applied for three cases of diffusive motion: free diffusion in an unrestricted space, diffusion in a limited volume, and jump diffusion in a crystal.