Temperature dependence of self- and N2-broadening coefficients of CH3Br ν6 band

Using absorption FT spectra (Bruker IFS 120, unapodized FWHM resolution ≈0.001 cm−1), about 1400 lines, between 880 and 1050 cm−1, and belonging to the ν6 band of both 12CH379Br and 12CH381Br isotopologues have been studied. Self- and N2-broadening coefficients are measured at various temperatures with an accuracy estimated to be around 10%. Their temperature-dependence exponents nself and nN2 have been derived with an accuracy estimated to be between 10% and 20%. A rotational dependence with the quantum number J has been observed for both nself and nN2, and has been empirically modeled using average values and polynomial expansions.