Vibronic Interactions in Vanadium Tetrachloride by Gas Electron Diffraction

Abstract
The molecular structures of VCl4 and TiCl4 have been determined by gas electron diffraction. The mean square amplitude of the Cl–Cl distance in VCl4 is found to be abnormally large compared with that of TiCl4. This is attributed to the vibronic interactions in VCl4. The observed mean square amplitude has led to the evaluation of the first-order vibronic interaction constant |a′|. Other experimental results, such as bond lengths, the shrinkage effect, and vibrational spectra are discussed in relation to the theory of vibronic interactions.