Collision Broadening in the Inversion Spectrum of Methyl Chloride at Pressures up to Two Atmospheres

Abstract

The power absorption coefficient a of microwaves of wave number v = 0� 333cm-1 by methyl chloride at 33� 7�C has been studied at pressures up to 2 atm, and the results are compared with theoretical predictions. Discrepancies which have previously been attributed to the effect of transitions between low.lying rotational states are shown to be due to three� body collisions. The collision diameter for pressure broadening of theinversion transition in methyl chloride is found to be 8�6 A; this is significantly larger an the figure of 7 . 2 A reported by earlier workerswho neglected the effect of three-body ollisions.