The characteristics of the faint Raman lines appearing in long exposures have been investigated for the molecules, SnBr4, SnCl4, and CCl4. All the lines observed have been classified as overtones and combination tones of the fundamentals. The depolarizations of the second‐order lines were measured by means of a Wollaston prism placed between the collimator lens and the dispersing prism of the spectrograph. The depolarizations were found to be in accordance with theory, on the assumption of tetrahedral symmetry for the molecules. The intensities of the second‐order lines relative to the fundamentals were measured. For the spherically symmetrical frequencies it is shown that the observed intensities can be explained by assuming that electrical and mechanical anharmonicities are both operative; in some cases counteracting one another and in other cases enhancing the effect of each other.
展开▼
