Abstract
The multiple-scattering and spherical-wave correction to the single-scattering-cluster (SSC) theory in the high energy region is presented. In this energy region the atomic scattering factors for elastic scattering are strongly peaked in the forward direction. The thermal vibration of atoms in the SSC model is also discussed. A large angle scattering is damped because of thermal vibration. Furthermore, the limitation to perform the numerical calculation is discussed.