Ab initio theoretical and experimental vibrational optical activity in some small organic molecules.

摘要

Vibrational optical activity in some small organic molecules was investigated by ab initio molecular orbital (at the SCF level) and experimental methods during the course of the present dissertation research work. Vibrational Raman optical activity of methyloxirane, methylthiirane, phenyloxirane and 3-methylcyclopentanone was computed using different basis sets and was found to exhibit remarkable qualitative correspondence with the experimental spectrum.; Vibrational analyses of tartaric acid and methyl lactate were done at the 6-31G level. The vibrational circular dichroism (VCD) spectrum of methyl lactate was compared with that of tartaric acid and some inferences were drawn relating the VCD spectra of these two compounds.; Localized molecular orbital calculations of VCD intensities using ab initio wavefunctions at different levels of basis sets were done for oxirane and cyclopropane and their deuterated analogs. The results were compared against those obtained from two other formalisms and the experimental values. For these two systems, the LMO method is seen to give a faithful representation of the experimental results.