SPECTRAL INTERPRETATION OF THE REFRACTIVITY AND DIELECTRIC VIRIAL-COEFFICIENTS OF ATOMIC GASES

Second electrooptical virial coefficients are expressed in terms of collision-induced intensity redistribution in absorption spectra of gases. Simple relations are obtained giving explicit frequency dependence of the contributions to the incremental dynamic polarizability due to pressure shift and asymmetric broadening of a single spectral line. The dispersion of the second virial coefficient is shown to be either normal, or reversed (anomalous), depending on the pattern of the absorption cross section redistribution.