High-resolution infrared spectra of ethanelike molecules and the barrier to internal rotation: The ν9, ν13 band of dimethylacetylene

The infrared spectrum of dimethylacetylene was measured with high resolution in the region of the perpendicular band of the CH stretching vibration and the Q branches were partially resolved in the bunches of Q branches. The upper limit to the torsional barrier was estimated to be 4 cm ^-1.