The Infrared Absorption Spectra of the Linear Molecules Carbonyl Sulphide and Deuterium Cyanide

Abstract

Carbonyl sulphide. The discovery of new vibration-rotation bands in the infrared absorption spectrum of carbonyl sulphide has made it possible to determine the vibrational energy level scheme of the molecule. The agreement between theory and experiment is quite satisfactory. Deuterium cyanide. The fundamental bands of deuterium cyanide ${\ensuremath{\omega}}_{2}$ at 570 ${\mathrm{cm}}^{\ensuremath{-}1}$ and ${\ensuremath{\omega}}_{3}$ at 2630 ${\mathrm{cm}}^{\ensuremath{-}1}$ have been measured with grating spectrometers. The former has a strong zero branch at 570.16 ${\mathrm{cm}}^{\ensuremath{-}1}$, and the fine structure lines on each side are well separated. From the line spacing the moment of inertia of the molecule is found to be 22.92\ifmmode\pm\else\textpm\fi{}${10}^{\ensuremath{-}40}$ gram ${\mathrm{cm}}^{2}$. A comparison of this value with the corresponding one for HCN, i.e., 18.72\ifmmode\pm\else\textpm\fi{}${10}^{\ensuremath{-}40}$ gram ${\mathrm{cm}}^{2}$, permits the calculation of the internuclear distances. From the positions of these two bands, together with those of the observed fundamentals of HCN, the zeroth order quadratic potential energy expression is computed.