Linewidths of HCl Broadened by H2, D2, and HCN

The linewidths in the 1–0 band of HCl broadened by H2, D2, and HCN have been measured at 297°K with a resolution of 0.02 cm−1. The experimental results are compared with linewidths calculated from Anderson's impact theory as extended by Tsao and Curnutte. The agreement between experiment and theory is good for HCl+D2 and qualitatively correct for HCl+H2 provided the small impact-parameter approximation of Fiutak and Van Kranendonk is used. For HCl+HCN, the agreement between experiment and theory is fair. Best-fit values for the quadrupole moments and hard-sphere diameters of HCl, H2, D2, and HCN are listed and compared with previous values.