Broadening, shifting, and line asymmetries in the 2]0 bandof CO and CO–N2 : Experimental results and theoretical calculations

Abstract:

We have measured the room temperature, widths, pressure shifts, and line asymmetry coefficientsfor many transitions of the first overtone band of CO and CO perturbed by N2 . The broadeningcoefficients were obtained with an accuracy of about 1%. The pure CO profiles have been fitted bya Voigt profile while the CO–N2 spectral profiles have been fitted with a Lorentz and an empiricalline shape model (HCv) that blends together a hard collision model and a speed-dependent Lorentzprofile. In addition to the Voigt, Lorentz, and HCv models, we have added a dispersion profile toaccount for weak line mixing. The line broadening and shift coefficients are compared tosemiclassical calculations employing a variety of intermolecular interactions. The line asymmetryresults are compared to line mixing calculations based on the energy corrected sudden ~ECS! model. The results indicate that effects other than line mixing also contribute to the measured lineasymmetry. © 2000 American Institute of Physics. @S0021-9606~00!01425-2#