The FT-IR spectra of pyridine and pyridine-d 5

Abstract

The high-resolution (0.06 cm −1) FT-IR spectra of pyridine and pyridine-d 5 at various path lengths (up to 10 m) have been obtained. These spectra reveal many new features that were not observed before. For example, the observation of many difference bands allows accurate determination of vibrational term values of some inactive and/or weak fundamental vibrations. The five C H stretching modes have been resolved for the first time. Frequency accuracy and internal consistency (since only high-resolution FT-IR data are used) are essential to the present analysis which provides accurate, isolated molecule term values for most of the fundamental vibrations of pyridine and pyridine-d 5. These results will be useful for more accurate force field analyses and serve as a guide for future, higher-resolution rotational studies for which the perturbations can now be predicted with more certainty.