Surface and bulk contributions to x-ray thermal diffuse scattering (Green's function approach)

The Green's function formalism is applied to the analysis of the surface co ntribution to the inelastic scattering of x-rays by acoustic modes of therm al excitations in a crystal. It is shown that the surface contribution to t hermal diffuse scattering (TDS) near the surface can become comparable to a nd can even exceed the volume contribution. The same formalism is applied t o the investigation of TDS in the case of dynamical diffraction, when an x- ray standing wave is generated in a crystal. TDS yield curves calculated ac cording to this model show good agreement with the experimental results.