Measurements of air and noble-gas broadening and shift coefficients of themethane R3 triplet of the 2 nu(3) band

By using a tunable diode laser spectrometer with one absorption White cell for low pressure and one photoacoustic cell for high pressure, line shape p arameters of the R3 tripler of the 2v(3) band of methane at 1.65 mum were m easured. The absorption line was recorded by using the wavelength modulatio n spectroscopy technique with first harmonic detection. The broadening and shift coefficients were obtained by fitting the first harmonic absorption s ignal while varying the pressure of different perturbing gases: air and nob le gases (helium, neon, argon, krypton and xenon). We present here the resu lts for the R3 tripler. The observed shift and broadening coefficients beha viors are discussed.