2ND-ORDER RAMAN-SPECTRA OF BENZENE AND HEXADEUTEROBENZENE IN THE GASEOUS-PHASE

We have photoelectrically recorded the Raman spectra of benzene and benzene-d6 in the gaseous phase at their vapour pressure at room temperature. In addition to the Raman bands of the fundamentals and some hot bands also many overtone and combination vibrations have been observed. For C6H6 the wavenumbers of 50 bands of second or higher order have been measured and 28 of these could be assigned to overtones and binary combinations. For C6D6 38 such bands have been detected, 19 of which could be assigned. Depolarization ratios have also been measured, most of the second order bands were found to be polarized. The results of the measurements can serve as a basis for the determination of improved values of anharmonicity constants of the free benzene molecule.