RAMAN OPTICAL-ACTIVITY - COMPUTATION OF CIRCULAR INTENSITY DIFFERENTIALS FOR BROMOCHLOROFLUOROMETHANE

The Raman optical activity (ROA) parameters for bromochlorofluoromethanc have been calculated using an atom dipole interaction (ADI) procedure. Raman intensities were measured in both liquid and vapor phases and molecular polarizability derivatives were determined. These Raman scattering parameters along with previously developed molecular force fields were used to evaluate the circular intensity differentials (CIDs) for all fundamental vibrational modes of (R)-HCBrCIF and (R)-DCBrClF. The predicted CIDs range from 10-5 to 10-3 with those for deformation modes being larger than those of stretching modes. Thus, these results are consistent in magnitude and mode type dependence with results reported on other molecules. Furthermore, the sign pattern of the CIDs of the three low-frequency modes of HCBrCIF corresponds directly to the CIDs reported for the skeletal deformation modes of «-phcnylelhyt isocyanatc. These results will serve as a model for the CIDs of other molecules where motion about an asymmetrically substituted carbon atom occurs. © 1979, American Chemical Society. All rights reserved.