Integrated Band Intensities of Ethylene (C212H4) by Fourier Transform Infrared Spectroscopy

Abstract

The integrated band intensities of ethylene (12C2H4) in the 640–3260 cm−1 region were determined by Fourier transform infrared (FTIR) spectroscopy. The infrared absorbance spectra of the ν7 and ν10, ν12, ν7+ν8, ν6+ν10, v11, and ν9 and ν2+ν12 bands of ethylene recorded at a resolution of 0.5 cm−1 were measured at an ambient temperature of 296 K at various vapor pressures ranging from 3×10−5 to 1×10−3 atm to obtain respective Beer-Lambert's law plots. The measured integrated band intensities in cm−1/cm atm were S(ν9andν2+ν12)=112.20±0.24, S(ν11)=55.35±0.14, S(ν12)=41.22±0.30, and S(ν7andν10)=328.66±16.55. In addition, the measured infrared band intensities of the ν7+ν8 and ν6+ν10 combination bands of ethylene are reported for the first time: S(ν7+ν8)=21.701±0.028 cm−1/cm atm and S(ν6+ν10)=2.568±0.025 cm−1/cm atm.

Accurate 12D dipole moment surfaces of ethylene

“…The sums of ab initio intensities up to J max = 30 for all fundamental 12 C 2 H 4 bands available in HITRAN-2012 database [8] differ from the empirical 305 evaluation by 0.38% for VTZ-F12 and by 1.26% for VQZ DMSs(Table ?? ).The overall integrated intensity in the 640 -3260 cm −1 range agrees with lowresolution determination by Lebron and Tan[47] to 0.45%. To our knowledge such a step forward in the computational spectroscopy becomes possible for the first time in case of rotationally resolved spectra of hexatomic molecules.…”

“…Lebron and Tan [47] have reported Fourier transform experimental determination of the absorbance area in ethylene infrared spectra at a resolution of 0.5 cm −1 with various gas pressures. They have distinguished five spectral intervals given in Table 3 where 260 the ethylene infrared opacity was the most significant.…”

“…d Obtained as a sum of VQZ ab initio line intensities for all bands contributing to each interval up to J max = 30. e Relative deviations [(S obs −S calc )/S obs ] in % between Ref. [47] and calculations for integrated line intensities. iments.…”

“…Interval-by-interval comparison of ab initio C 2 H 4 integrated intensities with low resolution measurements of Lebron and Tan[47]. In wavenumbers cm −1 .b Bands providing main contributions to considered interval.…”

First theoretical global line lists of ethylene (12C2H4) spectra for the temperature range 50−700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

“…Most available analyses of ethylene laboratory spectra only consider line positions. Integrated band intensities from low-resolution spectra have been measured by Lebron & Tan (2012). Few works in the literature were devoted to absolute intensity measurements in rotationally resolved spectra (Blass et al 2001;Rotger et al 2008;Vander Auwera et al 2014;Lafferty et al 2011;Ben Hassen et al 2012); Alkadrou et al (2016) but ethylene line-by-line intensity data above 3 µm range are essentially missing.…”