An Improved Gas Electron Diffractometer – The Instrument, Data Collection, Reduction and Structure Refinement Procedures

The improvement of a Balzers Eldigraph KD-G2 gas-phase electron diffractometer, previously operated at the University of Tübingen, is reported. The diffractometer was equipped with a state-ofthe-art telefocus electron gun, and high-energy radiation-sensitive imaging plates were introduced as detector system. A differential vacuum pumping system separating the diffraction chamber from the electron source was installed. A nozzle for the evaporation of compounds in a temperature range from 25 to 400 ◦C was constructed and its functionality proven by the structure determination of quinoline. Calibration, data reduction and structure refinement using standard procedures in connection with a selection of literature-known programs are described. The gas-phase structure of quinoline was determined, discussed and compared with ab initio and solid-state X-ray diffraction results.