Knowledge Bank

The results of recent studies of the relative line-broadening effects of foreign $gases1$ have been used along with the absolute values for the half widths of self-broadened CO lines reported by Hunt, Toth, and $Plyler2$ to obtain the half widths of CO lines broadened by $H2,D2,He,CH4,NH3,Ne,N2,Ar,CO2,N2O,Kr,$ and Xe. Plots of line half width vs line number m are in general agreement with similar plots given by Crane-Robinson and $Thompson3$. An interpretation of the results in terms of collisions involving the conversion of translational energy into rotational energy will be suggested. By making certain reasonable but relatively unimportant assumptions regarding the ranges of the effective intermolecular forces and by applying energy and angular-momentum conservation principles, we have been able to fit the experimental results for the first 21 lines in the R branch by introducing only two adjustable parameters for each of the foreign gases. Although the agreement between observed and calculated results is excellent, the suggested interpretation has certain shortcomings, which will be discussed.