Diode-laser measurements of He- and N₂-broadening coefficients and line-mixing effects in the Q-branch of the ν₁-ν₂ band of CO₂

He- and N-broadening coefficients have been measured for the lines Q2 to Q22 of the V-V (1001 ← 0101) band of CO near 720.80cm, using a tunable diode-laser spectrometer. The collisional widths have been obtained at low perturber pressures by fitting Voigt and Galatry profiles to the measured shapes of the lines. Spectra in the V-V band of CO in mixture with He and N have also been recorded at higher pressures. The deviations observed from an additive superposition of Lorentzian lines have been notably reduced by considering collision-induced line-mixing effects.