Knowledge Bank

“Recent theoretical studies have clarified certain aspects of electron scattering theory, confirming the essential correctness of Debye’s 1941 equation for the diffraction of electrons by gas molecules. According to this equation the time-average radial distribution of nuclear charge can he deduced from properly corrected electron intensity data. Mean internuclear distances and amplitudes of vibration so found depend upon temperature and isotope mass. Furthermore, mean distances are not interrelated simply by the laws at Euclidean geometry. A brief comparison will he made of the complicating effects of molecular vibration on spectroscopic and diffraction analyses. This will be followed by a description by a new method fur calculating the influence of anharmonic vibrations on structural parameters and a discussion of recent experimental diffraction results.”