Line parameters for hot methane v3 band broadened by H2 from 296 to 1100 K

Abstract

Methane (CH4) spectra in the v3 band near 3.3 µm were measured for 0 Torr, 50 Torr, 150 Torr, 240 Torr, 320 Torr, and 400 Torr pressure of added hydrogen. The spectra were recorded using a high resolution Fourier transform spectrometer. The CH4 spectra were measured at 5 different temperatures from room temperature up to approx 1100 K. A multi- spectrum non-linear least square fit method was used to determine the line parameters at each temperature. Voigt lineshape functions were used to determine the broadening and shifting of methane lines in the P and R branches. Temperature-dependence of coefficients were determined from a fit of line parameters as function of temperature. Finally, the dependence of pressure broadening (gamma0) and shift (delta0) parameters on the rotational quantum number (J) was studied.