20 December 1985 Study Of Anharmonic Vibrations By Low Frequency FT-IR Spectroscopy
Author Affiliations +
Proceedings Volume 0553, Fourier and Computerized Infrared Spectroscopy; (1985) https://doi.org/10.1117/12.970868
Event: 1985 International Conference on Fourier and Computerized Infrared Spectroscopy, 1985, Ottawa, Canada
Our research efforts in the area of anharmonic vibrations, which include the skeletal bending modes in quasilinear molecules, the ring puckering and ring bending modes in four- and five-membered rings, and the torsional modes for molecules with two internal C3, rotors, have been concentrated more recently on the determination of the asymmetric potential function governing the internal rotation in a number of three-membered ring carbonyl compounds, substituted allylic compounds, propenoyl halides and alkyl halides. Although asymmetric potential functions had been previously proposed for some of these molecules, relatively few of these can be given a significant level of confidence due to a number of experimental problems which have been previously encountered. For example, far infrared spectroscopy has been used in the past for the determination of asymmetric torsional frequencies but we have found that a resolution of at least 0.1 cm-1 needs to be used to record the low frequency data because many torsional bands are extremely sharp and therefore were not even observed with the relatively low resolution utilized. Additionally, insufficient resolution may result in misleading relative intensities of the Q-branches so that incorrect assignments have resulted. In many cases, due to symmetry, both infrared and Raman spectroscopic results are needed to identify the high and low energy conformers. Examples will be provided to demonstrate how asymmetric torsional data can be used to obtain potential constants.
© (1985) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. R. Durig, J. R. Durig, T. S. Little, T. S. Little, G . A. Guirgis, G . A. Guirgis, } "Study Of Anharmonic Vibrations By Low Frequency FT-IR Spectroscopy", Proc. SPIE 0553, Fourier and Computerized Infrared Spectroscopy, (20 December 1985); doi: 10.1117/12.970868; https://doi.org/10.1117/12.970868


Back to Top