The pressure-broadening effects of one atmosphere of air or of carbon dioxide on various infrared bands of hydrocarbons have been investigated. Large pressure-broadening effects are shown by ethylene at 10.52 microns and acetylene at 3.1 and 13.7 microns, moderate effects by acetylene at 7.4 microns and propylene at 10.95 microns, and small effects by 1-butene at 10.85 microns, trans-2-butene at 10.375 microns, and benzene at 9.50 microns. The variation of absorbance at several of the infrared absorption maxima of ethylene and acetylene has been investigated using varying partial pressures of air or carbon dioxide at fixed partial pressures of the 2 hydrocarbons.
A. P. Altshuller and A. F. Wartburg, "Pressure-Broadening Effects on Infrared Peak Intensities of Hydrocarbons," Appl. Spectrosc. 15, 67-69 (1961)