On the calculation of pressure-broadened linewidths for symmetric-top molecules using the modified Anderson theory
An approximation, accurate to better than 0.5%, to the Anderson-Tsao-Curnutte theory of linewidth is presented. This approximation is shown to be suitable for calculating linewidths of symmetric top molecules where dipole-dipole forces are dominant, but higher-order multipole terms are not negligible. Some insight is gained as to the relative importance of various types of collisions between interacting molecules from this approach to the calculation of the spectral linewidths for rotational states of molecules. Experimental results for CH 335Cl and CH 3127I are presented for comparison with the calculated results.