Raman Spectra of Hexachloroethane and Hexabromoethane

Abstract

Raman frequencies, relative intensities, and depolarization factors are reported for hexachloroethane and hexabromoethane. The relative intensities and depolarization factors were obtained by use of a Gaertner microdensitometer. The fundamental frequencies of hexachloroethane were used to calculate force constants from the equations used by Stitt for ethane. The Raman data indicate that the equilibrium configuration for hexachloroethane is that corresponding to the point group D_3d. The force constants so obtained were then used to calculate the values of the frequencies that are allowed by the selection rules in the infra‐red spectrum. Selection rules for the fundamentals, binary combinations, overtones of non‐degenerate frequencies, and overtones of degenerate frequencies up to the fourth overtone for any molecule whose symmetry is D_3h, D′_3h, or D_3d were worked out and are discussed.