The v3- v4 difference band contribution to the CCI4 symmetric stretch (v1) mode

James D. Gaynor
Anna M. Wetterer
Edward J. Valente, University of Portland
Steven G. Mayer, University of Portland

Journal of Raman Spectroscopy, 2015, Volume 46, 189-193.

© 2014 John Wiley & Sons

Linked version is final published version.

Abstract

The Raman spectrum of the symmetric stretching vibration (ν1) of liquid carbon tetrachloride observed at 295 K and reported repeatedly over the last 80 years clearly shows four of the five more abundant isotopomers at 440–470 cm−1. At the lower energy end of this spectrum, additional intensity due to isotopomeric contributions from the symmetric stretch for v = 1 2 (hotbands) partially overlaps the prominent v = 0 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 1) band at 462.5 cm−1becomes 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.