Line profile study from diode laser spectroscopy in the 12CH4 2v3 band perturbed by N2, O2, Ar, and He

We present a line profile study for two lines in the 2nu(3) band of CH4 recorded with a frequency stabilized tunable diode laser spectrometer. The broadening and narrowing (Dicke effect) parameters of the R(0) line perturbed by N-2, O-2, and He are derived from a simultaneous fitting of spectra at pressures from 20 to 300 Torr by using the soft and hard collision models. These parameters are determined for the A and F components of the unresolved R(3) manifold perturbed by N-2, Ar, and He from the line profile analysis of spectra at pressures between 50 and 500 Torr. The line mixing effect between the two F components is also taken into account and the absorber speed dependent effect on broadening is estimated for N-2 and Ar. (C) 2003 Elsevier Science (USA). All rights reserved.