VIBRATIONAL ANALYSIS OF NORMAL PARAFFINS
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Date
1951
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Ohio State University
Abstract
An infinite normal paraffin chain is assumed to be an infinite set of coupled $CH_{2}$ groups in a zigzag configuration. The general vibrations of the chain are considered to be combinations of motions of the $CH_{2}$ groups relative to one another, hindered rotations, and internal motions of the $CH_{2}$ groups. The normal modes have been obtained, using a linear valence-type force field and including all interactions allowed by symmetry between one $CH_{2}$ group and its two nearest neighbors on either side. Application of appropriate boundary conditions to the solutions for an infinite chain yields results which are in good agreement with the frequencies observed for chains of finite length, and which also explain the observed degradation and alternation of intensities on one side of a band head. The spacing of the fine-structure peaks gives information on the interaction force constants, and the intensity ratios give primarily the effect of the terminating methyl groups.
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Author Institution: Department of Physics and Astronomy, The Ohio State University