Knowledge Bank

An evaluation of the microwave absorption intensity law derived by Harrington has been conducted, using the three hyperfine components of the $J=0\to 1$ transition of methyl chloride. Excellent agreement between experimental and theoretical relative intensities is obtainable at pressures high enough that wall collisions may be ignored. Significant deviations from the predicted relative intensities and saturation powers are noted at low pressures. A method is described which allows the application of the intensity law to measurements using pressure and power combinations which do not produce complete saturation.