Raman spectroscopy is a powerful experimental technique, yet it is often missing from the undergraduate physical chemistry laboratory curriculum. Tetrachloromethane (CCl 4 ) is the ideal molecule for an introductory vibrational spectroscopy experiment and the symmetric stretch vibration contains fine structure due to isotopic variations of the molecule according to C 35 Cl x 37 Cl 4−x . We report simple theoretical predictions of the fine structure, calculation of Raman differential scattering cross sections, and discussion of the inherent asymmetry in the v 1 mode resulting from the different isotopes of chlorine. All calculations and discussion are appropriate for an undergraduate physical chemistry laboratory as either an independent dry lab or a supplement to a pre-existing vibrational spectroscopy lab.

In our previous article on CCl4 in this Journal, we presented an investigation of the fine structure of the symmetric stretch of carbon tetrachloride (CCl4) due to isotopic variations of chlorine in C35Clx 37Cl4–x . In this paper, we present an investigation of the contributions from both the v = 0 to v = 1 excitation and the v = 1 to v = 2 excitation. We report the calculation of spectral contributions from excited state vibrational transitions (hot bands). All calculations and discussion are appropriate for the undergraduate physical chemistry laboratory as either an independent dry lab or a supplement to a pre-existing vibrational spectroscopy lab.