Vibrational spectra of CCl4: isotopic components and hot bands. Part I

Room temperature (295 degrees K) infrared spectra of CCl4 have been measured covering the 4000-200 cm(-1) region. Bands ascribable to the isotopic components in the first overtone of the asymmetric deformation (2v4) mode and the combination of the symmetric and the asymmetric deformation (v2 + v4) mode regions are observed in agreement with the percentage distribution of various isotopes. From these observations, the first ever estimate of the isotopic band positions in the regions of the v4 and v2 modes at room temperature are obtained. Successful assignment of the isotopic bands in the asymmetric stretching (v3) and combination of the symmetric stretching and asymmetric deformation (v1 + v4) mode regions has been achieved and realistic values of all the v3/(v1 + v4) mode Fermi resonance parameters are obtained. The experimental results suggest that the transitions, where the initial levels are not the ground state, contribute significantly and give rise to a very complicated vibrational spectrum for CCl4 vapour.