The [nu]3-[nu]4 difference band contribution to the CCl4 symmetric stretch ([nu]1) mode

The Raman spectrum of the symmetric stretching vibration (ν1) of liquid carbon tetrachloride observed at 295K and reported repeatedly over the last 80years clearly shows four of the five more abundant isotopomers at 440-470cm-1. At the lower energy end of this spectrum, additional intensity due to isotopomeric contributions from the symmetric stretch for v=1[arrow right]2 (hotbands) partially overlaps the prominent v=0[arrow right]1 features, and accounts for about 18% of the integrated intensity at 295 K in agreement with theory. When these two patterns are modeled and subtracted from the experimental spectrum, a feature underlying almost exactly the C35Cl4 (v=0[arrow right]1) band at 462.5cm-1 becomes apparent. We propose that this feature is the ν3-ν4 difference band. Observations at lower temperatures, and of the combination bands, and the polarized Raman spectra are consistent with this hypothesis. Copyright © 2014 John Wiley & Sons, Ltd.