TRANSMISSION RESONANCE DIFFRACTION AND LOW IMPACT PARAMETER INELASTIC-SCATTERING OF HIGH-ENERGY ELECTRONS

Since the development of the theoretical treatment of transmission (bu lk) resonance scattering of high-energy electrons it has been anticipa ted that this type of many-beam diffraction could lead to a substantia l increase in the cross-section of all inelastic interactions characte rized by small impact parameters of electron-atom collisions. However, until recently ring Kikuchi patterns remained the only existing confi rmation of this prediction, showing the increase of the cross-section of thermal diffuse scattering due to resonance diffraction in the fina l state of the process of inelastic interaction. In this paper we repo rt the results of the first experimental observation showing the incre ase of the cross-section of inelastic scattering (X-ray production and high-angle backscattering) detected as a function of two angles of in cidence, i.e. the effect associated with the presence of resonance dif fraction in the initial state of the process of inelastic electron-ato m interaction in a crystalline environment. We discuss possible implic ations of our findings for atom site determination in transmission hig h-energy electron diffraction. (C) 1998 Elsevier Science B.V. All righ ts reserved.