The Isotope Effect in the Vibration Spectrum of CCl4

The fine structure in certain of the Raman lines of CCl4 observed by Langseth and interpreted by him as being due to a lack of symmetry in the four carbon valencies has been shown to be accountable for as a purely isotopic effect. Rosenthal's general theory of the isotope effect in molecules of this type has been applied to the case of CCl4 in an attempt to differentiate between two types of potential function which have been proposed for this molecule. The fine structure patterns predicted on the different theories have been worked out. Unfortunately the existing experimental data are not sufficiently good to allow a decision to be made as to which is the better function.