Infrared Spectra and Force Constants of Cyanoacetylene

Abstract

The infrared spectra of gaseous, liquid, and solid cyanoacetylene, H–C≡C–C≡N, have been observed in the region from 450 cm^—1 to 3400 cm^—1. Six of the seven fundamental vibrational frequencies expected for cyanoacetylene on the basis of a linear structure have been assigned and the remaining frequency has been estimated from observed combination bands. A force constant calculation has been carried out using a simple valence potential function.