Collision-induced first overtone band of H2 in binary mixtures H2-N2 and H2-CO

Enhancement spectra of the collision-induced absorption (CIA) of H2 in its first overtone region 7500-9500cm-1 in binary mixtures H2-N2 and H2-CO were studied at 298 K for base densities of H2 in the range 89-145 amagat and for partial densities of N2 and CO in the range 19-392 amagat. The observed spectra confirm that the isotropic overlap induction is absent in the 2-0 band of H2 unlike in the CIA spectra of the fundamental band of H2. Binary and ternary absorption coefficients were determined from the integrated absorption coefficients of the band. Enhancement absorption profiles of H2-N2 and H2-CO consist of a total of 434 components of quadrupolar double transitions. Profile analysis of the spectra was carried out using Birnbaum-Cohen line shape function for the individual components of the band and characteristic line shape parameters were determined from the analysis.