Measurements of Line Intensities and Self-broadening Coefficients in the ν2 Band of CH3I

Abstract

The line intensities and pressure broadening coefficients for transitions in the three branches of the ν2 parallel band of CH3I are measured for the first time for about 1317 lines with rotational quantum numbers 2 ≤ J ≤ 70 and 0 ≤ K ≤ 13 using a mono-spectrum fitting technique utilizing a Voigt profile. Five spectra have been recorded at room temperature (T = 297.6 K) with a high resolution Fourier transform spectrometer at pressures between 1.15 and 9.98 mbar. The measured intensities were used to derive the transition dipole moment squared for each line, the band intensity as well as the Herman–Wallis coefficients. These parameters were used to predict the values of line intensities. The band intensity was compared with previous works performed at medium resolution. The rotational dependencies of the self-broadening coefficients have been clearly observed and modeled using an empirical model. The average accuracies were estimated to be around 5 % for line intensities and self-broadening coefficients.The whole set of results is given as supplementary material for a possible use in atmospheric and industrial applications.