Multiple-Scattering Effects in High-Energy Electron-Molecule Collisions. II Polyatomic Molecules

Abstract

The Glauber theory of multiple scattering is applied to the elastic collisions of fast electrons with polyatomic molecules in an effort to explain deviations between theory and experiment in recent molecular structure determination by electron diffraction. The full scattering amplitude is developed inclusive of all double-scattering contributions, with the differential cross section for the process given up to terms representative of the interference between single and double scattering. For sufficiently energetic incident electrons, the multiple-scattering contributions to the differential cross section are shown to reduce to simple analytic forms. In particular, the three-atom single-double interference term is shown to be an oscillatory function of momentum transfer. Application of the approximate formulas to the rhenium hexafluoride molecule gives excellent agreement with the experimental results of Jacob and Bartell.