Infra-Red and Raman Spectra of Polyatomic Molecules XII. Methyl Acetylene

Abstract

The infra‐red absorption of methyl acetylene gas has been studied between 2.5 and 25μ; the Raman spectrum of the liquid has been measured. A complete vibrational analysis is given, and the thermodynamic properties of the gas, between 250° and 1000°K, are tabulated. A normal coordinate treatment has been carried out, in which all force constants were determined a priori from other molecules. The ten fundamentals are calculated with an average error of 1.1, and a maximum error of 2.3 percent.