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The near‐IR spectrum of polyethylene, polyethylene glycol, and polyvinylethyl ether have been measured. The CH and OH stretch and bend absorptions have been assigned using local mode theory. The CH stretch anharmonicities are about 57 cm−1, typical of CH anharmonicities in molecular samples. The CH bend anharmonicities are 7, 10, and 11 cm−1, respectively, for polyethylene, polyethylene glycol, and polyvinylethyl ether. The CH bend absorption intensities decrease by about a factor of 4 allowing these bending transitions to be observed up to the fourth overtone transition. © 1996 John Wiley & Sons, Inc.

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The gaseous near-infrared and visible absorption spectra of pyrrole and pyrrolidine have been measured for the first through fourth N-H stretch vibrational overtones and the second through fourth C-H stretch overtones. The C-H overtone features follow the simple local mode expression with anharmonicities of 53.9 f 0.5 cm-' for pyrrole and 60 f 2 cm-' for pyrrolidine. Multiple transitions observed in the N-H stretching regions indicate the presence of vibrational coupling to other vibrational modes. This assignment is confirmed by the first and third N-H vibrational overtone spectrum of gaseous pyrrole-d4. For comparison, the visible spectra of neat liquid pyrrole, dilutions of pyrrole in carbon tetrachloride, and neat liquid pyrrolidine were obtained by direct absorption spectroscopy. The pattern of multiple peaks for the N-H absorption region also appears (shifted 200 cm-l to the red) in solution-phase pyrrole. This shift of all the peaks results from the intermolecular interactions of the N-H in the liquid; however, the preservation of the peak splittings indicates that this splitting is a result of intramolecular vibrational coupling. The spectrum of pyrrolidine is remarkably similar to that of pyrrole, suggesting the same vibrational coupling exists for both compounds.

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