Electron diffraction studies of supersonic jets. I. Apparatus and methods

Abstract

We describe the apparatus and methods used to obtain electron diffraction patterns of low‐temperature species produced from molecules seeded into supersonic expansions of helium or neon carrier gases. Although systems designed for molecular beam or spectroscopic studies are unsuitable for electron diffraction, alternative arrangements were found that give diffraction patterns of good quality. Characteristics of gas jets issuing from different nozzle designs are discussed. Procedures are outlined for separating the desired signal from considerable background scattering by the carrier gas and to correct for broad gas density profiles in analyses of diffraction data.