The Distribution of Gas Molecules at the Diffraction Center in the Electron Diffraction Experiment

A method has been proposed for estimating the distribution of gas molecules at the diffraction center in order to evaluate the correction for finite sample size in gas electron diffraction. The distribution measured in this way has been interpreted by a simple model regarding the motion of the gas molecules in the vicinity of the nozzle. A slight asymmetry of the nozzle construction produces in the atomic distances a deviation which cannot be disregarded if an accurate measurement is desired.