INFRARED SPECTRA AND INTERNAL ROTATION IN PROPANE, ISOBUTANE AND NEOPENTANE

The infrared spectra of propane, isobutane and neopentane were recorded at high path-length × pressure conditions between 200 and 800 cm-1. A large number of combination bands were observed and assigned, and values for the torsional frequencies of isobutane and neopentane were derived from the combination bands. Potential barriers to internal rotation were calculated from the torsional frequencies and are compared with other results available from the literature. © 1969.