Vibrational Spectrum and Vibro-Rotational Analysis of Cyanopropyne

The interpretation of the vibrational spectrum of cyanopropyne (CH₃–C≡C–C≡N) in the gas, liquid, and solid states has been carried out. The gas spectrum under medium resolution allows the determination of a few Coriolis constants. The rotational constants obtained from the infrared spectrum are in agreement with those from the microwave spectrum. Bandwidths in the liquid and solid states are accounted for by hindered rotations. Thermodynamic properties are evaluated taking into account a correction for the Coriolis $\xi$ coefficients.