Excited electronic states of ethylene sulfide. Circular dichroism study of (+)-(R,R)-2,3-dimethylthiirane

The excited electronic states of an optically active substituted ethylene sulfide ((+)-(R,R)-2,3-dimethylthiirane, DMT) is discussed in light of vacuum-UV absorption and circular dichroism (CD) spectra and ab initio self-consistent-field calculations. Experimental and calculated excitation energies and oscillator and rotational strengths are compared and provide the basis for the assignment of the excited electronic states. In the energy region below 2100 Å all the observed bands are assigned as an n_s → Rydberg transitions.