ANALYSIS OF THE SPECTRUM OF ETHYLENE IN THE $800$--$1500$ CM$^{-1}$ REGION USING TENSORIAL FORMALISM: FREQUENCIES AND INTENSITIES

Abstract

Recently, we have presented a tensorial formalism} {\bf 217}, 239--248 (2003).}$^,$} {\bf 95}, 521--538 (2005).} adapted to the spectroscopy of X$_2$Y$_4$ molecules. It is based on formalisms already developed in Dijon for spherical-top molecules} {\bf 228}, 620--634 (2004).} as well as on the work of Sartakov} {\bf 185} 31--47 (1997).}. This approach has the advantages to allow a systematic development of rovibrational interactions and to make global analyses easier to perform. We have used this tool to perform a re-analysis of the $\nu_{10}/\nu_7/\nu_4/\nu_{12}$ tetrad both in frequencies and intensities in the $800$--$1500$ cm$^{-1}$ region. We have used 8943 infrared data in the $\nu_{10}/\nu_7/\nu_4$ region from W. E. Blass' atlas} {\bf 71}, 47--60 (2001).} completed by 5420 more recent data in the same range} {\bf 104}, 273--292 (2006).} (207 of these having a precision of a few $10^{-6}$ cm$^{-1}$) and by 1138 data in the $\nu_{12}$ region from a spectrum recorded in Brussels. We obtain a global reduced RMS of $0.54$ for line positions, which is comparable to the result of Ref. {\it f}. Concerning line intensities, we used 10657 data from Blass' atlas and 25 high-precision diode laser data} {\bf 59} 421--426 (2003).}. We obtain a 11.6 \% RMS in this case.