PRESSURE BROADENING STUDIES ON VIBRATIONROTATION BANDS. IV. OPTICAL COLLISION DIAMETERS FOR FOREIGN-GAS BROADENING OF CO AND DC1 BANDS,

Results are given for the pressure broadening of lines in the vibration-rotation bands of carbon monoxide and deuterium chloride, by a wide variety of added gases including both non-polar and polar molecules. Optical collision diameters have been calculated and considered in relation to the interaction forces likely to be involved. For carbon monoxide, a rough correlation is found between the optical collision diameter and the interaction potential for non-polar broadeners where dispersion forces are dominant, but derivations occur with some polar broadeners. Similar data for deuterium chloride illustrate the importance of dipolar forces, but no simple theory explains the results satisfactorily. The variation of line width with J quantum number is discussed. Author