%The 28th Colloquium on High Resolution
%Molecular Spectroscopy
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\title{HIGH-RESOLUTION SPECTROSCOPY AND ANALYSIS OF THE 3 $\mu$m REGION OF C$_2$H$_4$ IN NATURAL ISOTOPIC ABUNDANCE.}



\author{\underline{\FirstName O. \LastName BEN FATHALLAH}}
\address{Universit\'e de Reims Champagne Ardenne, CNRS, GSMA UMR 7331, 51097 Reims, France, Laboratory of Spectroscopy and Molecular Dynamics, National Superior School of Engineering of Tunis, 5 Av Taha Hussein, 1008
	Tunis, Tunisia}

\author{\underline{\FirstName M. \LastName ROTGER}, \underline{\FirstName M. \LastName REY}}
\address{Universit\'e de Reims Champagne Ardenne, CNRS, GSMA UMR 7331, 51097 Reims, France}

\author{\underline{\FirstName H. \LastName AROUI}}
\address{Laboratory of Spectroscopy and Molecular Dynamics, National Superior School of Engineering of Tunis, 5 Av Taha Hussein, 1008
	Tunis, Tunisia}
	
\author{\underline{\FirstName V. \LastName BOUDON}}
\address{Lab. ICB, UMR 6303 CNRS/Univ. Bourgogne, 9, av. Alain Savary, B.P. 47870, F-21078 Dijon, France}



\author{\underline{\FirstName J. \LastName VANDER AUWERA}}
\address{SQUARES, C.P. 160/09, Universit\'e Libre de Bruxelles, 50 avenue F. D. Roosevelt, B-1050 Brussels, Belgium}

\author{\underline{\FirstName M.A. \LastName  LORO\~NO GONZALEZ}}
\address{Oficina 410, Departamento Acad\'emico de Fisicoqu\'imica, Facultad de Qu\'imica e Ingenieria Qu\'imica, Universidad Nacional Mayor de San Marcos, Lima, Peru}
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			Aug. 28 - Sept. 1, 2023}}}
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	\index{C$_2$H$_4$}

Ethylene is a natural gaseous compound present in the atmosphere of the Earth but also observed in the atmospheres of outer solar system bodies such as Neptune and Titan\footnote{G.S. Orton et al, \textit{Icarus}, \textbf{70}, 1-12, (1987)} \footnote{A. Coustenis et al, \textit{Icarus}, \textbf{124}, 54-76, (1989)}. Optical remote sensing of this species in these environments requires knowledge of spectroscopic parameters characterizing its spectrum. Such an information is compiled in databases,\footnote{I.E. Gordon et al, \textit{J. Quant. Spectrosc. Radiat. Transf.}, \textbf{277}, 107949, (2022)}$^{,}$\footnote{T. Delahaye \textit{et al.}, \textit{J. Mol. Spectrosc}, \textbf{380}, 111510, (2021)} their improvement being a long-lasting, constant effort.

We present here a detailed analysis and modeling of the strongly absorbing $\nu_9$ and $\nu_{11}$ fundamental bands of C$_2$H$_4$ observed in the 3 $\mu$m region. Due to the complexity of the observed spectrum, we have built a reasonably complex polyad scheme that includes some fundamental and combination bands previously analyzed using the tensorial formalism developed in Dijon for asymmetric-top molecules\footnote{J.P. Champion et al, \textit{Academic Press Inc.}, 339-422, (1992)}. A four-polyad system has been used to analyze a region where mainly five rovibrational modes: $\nu_9$, $\nu_{11}$, $\nu_2 + \nu_{12}$, $\nu_2 + \nu_{10}$, and $2\nu_{10} + \nu_{12}$ of the ethylene emerge.
A first frequency analysis has been performed, providing 3328 assignments and 87 adjusted parameters with a root mean square of $5.9 \times 10^{-3}$ cm$^{-1}$ and a standard deviation of $2.0 \times 10^{-3}$ cm$^{-1}$.
The line intensities were then fitted with a root mean square deviation of 1.9\%, using parameters determined from the analysis of the line positions. 
The band intensities were also determined and compared with previous work.
A new line list of calculated lines in the 2900-3300 cm$^{-1}$ region will be proposed to be added to the ECasDa, HITRAN\footnote{I.E. Gordon et al, \textit{J. Quant. Spectrosc. Radiat. Transf.}, \textbf{277}, 107949, (2022)}, and GEISA databases\footnote{T. Delahaye et al, \textit{J. Mol. Spectrosc}, \textbf{380}, 111510, (2021)}.


	
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