A quantum study of argon induced line mixing in ammonia doublets

Abstract

Abstract We present a theoretical study of pressure broadening and coupling coefficients for selected doublets of the ν 4 band of ammomia in argon bath. Generalized spectroscopic kinetic energy dependent cross sections are determined quantum mechanically making use of available NH3-Ar potential energy surfaces. Thermally averaged values at various temperatures are also provided. Results are in overall good agreement with data available in the literature. A further study focusses on the speed dependence of the corresponding line shape parameters. The pressure broadening coefficients are found to have a well marked speed dependence while the intradoublet coupling terms show a small speed dependence at room temperature.