Polarisation of Raman scattering

Abstract

The use of an improved technique has enabled us to obtain more precise measurements than formerly of the polarisation of the lines in Banian spectra. A systematic study has now been made with many liquids. An important result obtained is that no line has a depolarisation greater than 6/7, and that earlier reports by various workers indicating a larger depolarisation in certain cases are not correct. The limiting value of 6/7 is obtained in many instances, especially in all cases of a rotational scattering, whether by gases or by liquids. Many vibration lines also exhibit this high degree of depolarisation, as, for example, the frequencies 605,1584, and 1605 of benzene, the two bands at 189 and 1398 in formic acid, the line at 750 in thiophene, the frequencies 106, 131, and 403 in tin tetrachloride, and the corresponding lines given by the tetrachlorides of carbon, silicon, and titanium. In all these cases, the explanation suggested in the last paragraph of Bhagavantam's note in NATUBE of Jan. 30, 1932 (p. 167), is evidently applicable.