Extension of the exact trajectory model to the case of asymmetric tops and its application to infrared nitrogen-broadened linewidths of ethylene

Abstract

The model of exact trajectories involved in a semiclassical computation of (vib)rotational linewidths and shifts is extended to the case of asymmetric top colliders. General expressions for the second-order contributions to the scattering matrix are given which define the pressure broadening and shift of the line. This theoretical approach is tested on the particular case of the infrared ${\ensuremath{\nu}}_{7}$ band linewidths of ${\text{C}}_{2}{\text{H}}_{4}$ broadened by ${\text{N}}_{2}$ which is frequently required for atmospheric applications. The computed linewidths compare favorably with available experimental data.