Raman Intensity Studies on CCl4 in Various Systems

Solution measurements are presented of the Raman intensity changes occurring in the four fundamental vibrations of CCl4 upon changing from “inert” solvents to ones which can act as electron donors. Donor solvents containing oxygen have little or no effect on the Raman vibrational intensities of CCl4, while significant changes are found in the intensities of ν1, ν3, and ν4 in solutions containing aromatic and amine donors. The nature and magnitude of the observed Raman intensity changes are similar in the latter solutions suggesting that they are caused by a common effect. The observed changes in the intensities of the CCl4 fundamentals are analyzed in terms of changes in bond polarizability parameters. It is concluded that the observed intensity changes are due to specific intermolecular interactions, such as weak charge transfer complex formation.