Knowledge Bank

Enhancement of the collision-induced absorption (CIA) spectra of the first overtone band of $H2$ in the $H2-Kr$ and $H2-Xe$ binary mixtures were recorded at 295 K for base densities of $H2$ in the range 30-57 amagat and for partial densities in the range 50-250 amagat for each of Kr and Xe. The observed spectra consist fo single transitions $O2(J),Q2(J)$, and $S2(J)$ corresponding to the selection rule $\Delta J=-2,0$, and 2, respectively. Binary, ternary, and quarternary absorption coefficients of the band arising from collisions of the type $H2-X,H2-X-X,H2-H2-X,H2-X-X-X,H2-H2-X-X$, and $H2-H2-H2-X$, where X represents Kr or Xe, have been determined. The spectra are interpreted fully in terms of the quadrupolar induction $mechanism.a$ Analysis of the absorption profiles of the observed spectra was carried out using the Birnbaum-Cohen line-shape $functionb$ for individual components of the band and characteristic line shape parameters were determined from the analysis.