Infrared spectroscopy at high temperature : N 2 - and O 2 -broadening coefficients in the ν4 band of CH 4

•First determination of the N2- and O2-broadening of lines in the ν4 band of methane at high temperature were realized.•Set-up and development of a high temperature absorption cell for infrared spectroscopy was realized.•N2- and O2-broadening temperature dependence of lines in the ν4 band of methane were measured accuracy.•The line parameters were measured by high resolution diode-laser spectroscopy.•The line parameters were deduced from Voigt, Rautian-Sobel’man and Galatry fits.