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.