On the determination of equilibrium geometries and potential functions of simple polyatomic molecules from electron diffraction

Abstract

The degree to which current electron diffraction (ED) techniques allow reliable determination of equilibrium geometries and potential functions of simple molecular systems is studied. Special attention is paid to the choice of the model potential function in the diffraction analysis. The main calculations were performed using accurate diffraction data on SO2 and SF6 available from the literature. Routine electron diffraction data on PbCl2 and PbBr2 obtained at Moscow University were also treated and found to be reasonably informative regarding bond stretching anharmonicity. Compelling evidence has been presented that any unfavorable situation in the ED analysis of equilibrium geometries and force fields of molecules can be substantially improved by augmenting scattering observations with reliable inferences from vibrational spectroscopy data. This useful cooperation of techniques is shown to be most powerful in efforts to solve equilibrium geometries and molecular dynamics.