15min:
ANALYSIS OF THE SPECTRUM OF ETHYLENE IN THE 800--1500 CM-1 REGION USING TENSORIAL FORMALISM: FREQUENCIES AND INTENSITIES.

M. ROTGER, V. BOUDON, Laboratoire de Physique de l'Uni\-versité de Bourgogne, UMR CNRS 5027, 9, av. Alain Savary, B.P. 47870, F-21078 Dijon Cedex, France; A. FAYT, Molecular spectroscopy laboratory, Université Catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-La-Neuve, Belgium; J. VANDER AUWERA, Service de Chimie Quantique et Photophysique, C.P. 160/09, Université Libre de Bruxelles, 50 avenue F.D. Roosevelt, B-1050 Brussels, Belgium.

Recently, we have presented a tensorial formalism\footnoteW. Raballand, M. Rotger, V. Boudon and M. Loëte, J. Mol. Spectrosc. 217, 239--248 (2003)., adapted to the spectroscopy of X2Y4 molecules. It is based on formalisms already developed in Dijon for spherical-top molecules as well as on the work of Sartakov. 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 nu10/ nu7/ nu4/ nu12 tetrad both in frequencies and intensities in the 800--1500 cm-1 region. We have used 8943 infrared data in the nu10/ nu7/ nu4 region from W. E. Blass' atlas completed by 5420 more recent data in the same range (207 of these having a precision of a few 10-6 cm-1) and by 1138 data in the nu12 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. f . Concerning line intensities, we used 10657 data from Blass' atlas and 25 high-precision diode laser data. We obtain a 11.6 % RMS in this case.