Manifestation of dipo le-di pole intermolecular forces in organic compounds

Raman spectra were obtained for -, -, and -picolines in the gaseous state and in the liquid at various temperatures. Most of the observed frequencies were assigned by comparison with the spectra of pyridine and toluene. A phase shift was observed in the frequencies on passing from gas to liquid; it was interpreted in terms of local dipole-dipole interactions, and a correlation was established with the dipole moment of the molecule. The widths of a series of lines in the spectra of the picolines in the liquid state were measured. Analysis of the results revealed a relative contribution from Brownian rotational movement of the molecules and fluctuations of the dipole-dipole forces.Translated from Izvestiya VUZ. Fizika, Vol. 11, No. 8, pp. 87–93, August, 1968.The authors thank M. F. Vuks for kindly providing the compounds.