Theory of the Width and Shift of Molecular Spectral Lines in Gases

Abstract

A theory is developed for linewidths and line shifts in molecular spectra of gases. A semiclassical method is used, which does not make the approximations of perturbation theory and a straight‐line trajectory upon which previous work has been based. General formulas are given for linewidths and line shifts in microwave, infrared and Raman spectra of linear molecules. Numerical application of the results is made to the widths of a number of spectra, and the results are in good agreement with both the magnitude and J dependence of the experimental values.