Localized molecular orbital calculations of vibrational circular dichroism. I. General theoretical formalism and CNDO results for the carbon–deuterium stretching vibration in neopentyl-1-d-chloride

Abstract

The theoretical basis and methodology for the calculation of vibrational circular dichroism (VCD) intensities using the localized molecular orbital (LMO) model are described. In this approach VCD intensities are determined from the motions of both nuclei and centroids of localized molecular orbitals for individual normal modes of vibration. The concepts and approximations inherent in the LMO model are discussed and then illustrated for the C–D stretching mode of neopentyl‐l‐d‐chloride, where favorable comparison to experimental measurement and previous fixed partial charge calculation is found. The necessity of using localized molecular obitals is demonstrated by comparison to results obtained using nonlocalized molecular orbitals. The LMO–VCD result presented here is the first example of the use of an all‐valence electron model to determine VCD intensity.