Theory of Pressure Broadening of Microwave Spectral Lines

Abstract

A theory of pressure broadening of spectral lines is presented which is applicable to microwave spectra. It is an extension of the Anderson theory to the case of overlapping lines. The interference of neighboring lines is taken into account by the use of a relaxation matrix. The diagonal elements of this matrix correspond to linewidths and are calculated in the same way as in previous theories. The off-diagonal matrix elements are also calculated from the intermolecular interaction. Application is made to the ammonia and oxygen spectra.