FREQUENCY ANALYSIS OF THE 10 $\mu$m REGION OF THE ETHYLENE SPECTRUM USING THE $D_{2h}$ TOP DATA SYSTEM.

Abstract

New high resolution IR spectra of the $\nu_{10}/\nu_7/\nu_4$ region, lying from 600 cm$^{-1}$ to 1200 cm$^{-1}$ have been recorded in Brussels. They are used simultaneously with a previous spectrum of the $\nu_{12}$ band, also recorded in Brussels, to perform the analysis of the $\nu_{10}/\nu_7/\nu_4/\nu_{12}$ region, lying from 600 cm$^{-1}$ to $1500$ cm$^{-1}$. Following our work devoted to the $\nu_{12}$ band considered as isolated, we performed a frequency re-analysis of the $\nu_{10}/\nu_7/\nu_4/\nu_{12}$ infrared tetrad in the $600 - 1500$ cm$^{-1}$ region, thanks to the tensorial formalism developed in Dijon for X$_2$Y$_4$ asymmetric-top molecules, {\bf 217} 239--248 (2003).} and the XTDS software package, {\bf 251} 102--113 (2008). }. Including the strong Coriolis interaction affecting the upper vibrational levels $10^1$, $7^1$, $4^1$ and $12^1$, a total of $11727$ lines have been assigned and fitted as a tetrad with a global root mean square deviation of $0.338 \times 10^{-3}$ cm$^{-1}$.