Circular Dichroism of Oxiranes: An Independent Systems/Perturbation Approach

: The circular dichroism (CD) spectra of the first two Rydberg transitions of alkyl-substituted oxiranes are interpreted by an independent systems/perturbation approach. When alkyloxirane compounds are treated as an achiral oxirane ring perturbed by alkyl substituents, quantitative relationships between CD and oxirane structure are obtained. The dipolar coupled-oscillator model of Kirkwood and Kuhn proves to be the only significant mechanism for both the n(0) → 3s and n(0) → 3p transitions. The static coupling model suggested by Gedanken et al. to account for the sign of the n(0) → 3s transition does not account for the variation in CD magnitudes that is observed.