Concentration dependent depolarized Rayleigh scattering of dimethylformamidehyphen;h7 and hyphen;d7 in CCl4solution

摘要

The formulas derived in our previous paper on the first moments of farhyphen;infrared and depolarized Rayleigh spectra are applied to the study of dimethylformamide (DMF) and its deuterated derivative in carbon tetrachloride solution. Changes in the peak and average frequencies of theR(ohgr;) representation of the depolarized Rayleigh wing data are measured as a function of concentration and compared to limited farhyphen;infrared absorbance spectra of the more dilute solutions. The measured average frequencies of the DRS data agree well with those calculated from the area under the imaginary correlation function divided by time, and with the values calculated from the first term in the series expression for ohgr;macr; in terms of fourth and higher even moments. Collisional contributions to the spectral moments complicate the determination of mean square torques and orientational correlations from the DRS spectra. The first and second moments were found to be larger than the theoretical values for purely reorientational scattering and were fairly independent of concentration. The data suggest that the additional scattering is due to a dipolendash;induced dipole contribution to the polarizability agr;isdot;Tithinsp;jsdot;agr;j.