Measured and calculated O2-broadening coefficients of C2H4 in the 1800–2350 cm-1 spectral region. (June 2019)

• Record Type: Journal Article
• Authors: Hassen, A. Ben; Galalou, S.; Aroui, H.; Landsheere, X.; Tchana, F. Kwabia
• Is Part Of: Journal of quantitative spectroscopy & radiative transfer. Volume 230(2019)
• Page Start: 106
• Page End: 114
• Publication Date: 2019-06
• Subjects: Ethylene -- C2H4 -- Fourier transform infrared spectroscopy -- O2-broadening coefficients -- Air-broadening coefficients -- Robert and Bonamy formalism; Spectrum analysis -- Periodicals; Radiation -- Periodicals; Analyse spectrale -- Périodiques; Rayonnement -- Périodiques; Radiation; Spectrum analysis; Periodicals; 543.0858
• DOI: 10.1016/j.jqsrt.2019.04.003
• Languages: English
• ISSNs: 0022-4073

Abstract

Highlights: Fourier transform spectra of C2 H4 in the 5 µm region have been recorded. O2 and air-broadening coefficients have been retrieved for 590 lines of C2 H4 at t = 295 K. A mono-spectrum fitting procedure of Voigt profiles is used. O2 -broadening coefficients have been calculated using the semiclassical Robert–Bonamy formalism. Vibrational and rotational dependence of broadening coefficients is discussed. Abstract: The goal of this study is to measure and calculate for the first time the O2 -broadening coefficients of ethylene (C2 H4 ) in the 5 µm region. High-resolution Fourier transform spectra were recorded at various pressures for the whole 1750–3000 cm -1 spectral range. Using these spectra, a large set of 590 O2 -broadening coefficients was measured for the ν7 + ν8, ν4 + ν8, ν6 + ν10, ν6 + ν7, ν3 + ν10 and ν4 + ν6 bands. The broadening coefficients were measured using a mono-spectrum non-linear least squares fitting procedure of Voigt profiles which appeared to properly model the observed molecular line shapes within the noise level. These coefficients are compared to theoretical results calculated with the semi-classical Robert and Bonamy formalism in which the intermolecular potential includes electrostatic and dispersion energy contributions. These results are generally in satisfactory agreement with experimental data. The average discrepancy 〈 ( ( γ m e a − γ c a l ) / γ m e a ) × 100 〉 and the absolute difference 〈 ( | γ m e a − γ c a l | / γ m e a ) × 100 〉 between the measured and calculated values for 590 lines are (−2.3 ± 8.9)% and (7.3 ± 5.5)%, respectively. The rotational and vibrational dependences of O2 -broadening coefficients are examined. The present results of C2 H4 O2 and those of C2 H4 N2 are used to determine the corresponding C2 H4 -air system. Comparison between obtained results leads to an average value of the absolute difference of (7.2 ± 5.5)%.