The First Rotational Analysis of the Infrared Spectrum of Dimethylacetylene

Abstract

The perpendicular fundamental bands of dimethylacetylene have long been of interest to spectroscopists. This is because it is in these bands that two interesting effects manifest themselves. The first of these effects is the splitting of certain rotational lines caused by the small barrier to internal rotation. And the second effect is the shift of intensity within the band due to the coupling (through the acetylene bond) of the perpendicular methyl vibrations from one end of the molecule to the other.