Temperature- and pressure-dependent midinfrared absorption cross sections of gaseous hydrocarbons.
Transmittance spectra of four gaseous hydrocarbons were measured by using a Fourier transform infrared spectrometer. The analyzed substances are propane, n-butane, ethanol, and iso-octane (2,2,4-trimethyl-pentane). Mixtures of hydrocarbons and nitrogen were prepared and analyzed in an optical cell between 298 and 473 K at pressures up to 1800 kPa. Molecule specific absorption cross sections were calculated for different temperatures and pressures that are relevant for technical absorption measurements. Dependences of the spectral absorption cross sections, as well as the integrated absorption cross sections on temperature and pressure, were investigated.