Diode-Laser Measurements of He-Broadening Coefficients in the v₆ Band of ¹²CH₃F

He-broadening coefficients are measured for 28 lines of CHF in the Q (K = 0, ΔK = 1, ΔJ = 0) and Q (K = 6, ΔK = 1, ΔJ = 0) branches of the v band, using a tunable diode laser spectrometer. The collisional widths obtained by fitting Rautian profiles to the measured shapes of the lines are slightly larger than those derived from Voigt profiles. The broadening coefficients for the lines belonging to the same low J transitions are significantly greater in the Q branch than in the Q branch. Moreover, they decrease on the whole with increasing J in the Q branch and tend to increase from J varying from 7 to 10 in the Q branch. These trends may be approximately reproduced by calculations based on a semiclassical impact theory of collisional broadening.