CO–Ar continuum under the rotational band: can super-Lorentzian wings be involved?

The CO-Ar continuum absorption was retrieved from spectrum recordings in the far-infrared range (40-160 cm^-1) using the Fourier spectroscopy technique with a synchrotron radiation source. The expected continuum pressure dependences were obtained. The continuum retrieved from the high-resolution spectra after subtracting the calculated resonant spectrum was consistent with the continuum measured at low resolution in the microwindows between lines. The observed continuum agrees well with the bimolecular absorption model constructed on the basis of the second virial coefficient and redistribution of integrated absorption from resonant CO lines to the continuum. We discuss the origin of the intensity depletion effect and propose a semiempirical model for the far wings which considers collision duration and is consistent with the experimental data.