1. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Frequency Analysis of the 10 μm Region of the Ethylene Spectrum using the D 2h Top Data System M.-T. BOURGEOIS, M. ROTGER, Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR 7331 CNRS-Université de Reims Champagne-Ardenne, Moulin de la Housse, BP 1071, F-51170 Reims Cedex, France M. TUDORIE, 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 V. BOUDON, Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne, 9. Av. A. Savary, BP 47870, F-21078 Dijon Cedex, France

2. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Contents I.The C 2 H 4 molecule and its modes II.IR spectroscopy at ULB III.Theoretical model IV.Band analysis and simulation V.Perspectives for C 2 H 4 spectroscopy

3. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 I. The C 2 H 4 molecule and its modes

4. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 The 12 normal modes of C 2 H 4 ν(Ag)ν(Ag)ν(Ag)ν(Ag)ν(Ag)ν(Ag)ν(Au)ν(Au)ν  (B 2g )ν  (B 2g ) 3026 cm -1 1623 cm -1 1343.3 cm -1 1025.6 cm -1 3083.4 cm -1 1225.4 cm -1 ν  (B 2u )ν  (B 3g )ν  (B 3u )ν  (B 3u )ν  (B 1u )ν  (B 1u ) 948.8 cm -1 939.9 cm -1 3104 cm -1 825.9 cm -1 2988.6 cm -1 1442.4 cm -1 IR active Raman active Inactive I r representation

5. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 II. FTIR experiment at ULB

6. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 FTIR Experiment at ULB Bruker IFS 125 HR FTIR spectrometer

7. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Static cell at ULB 1.72 m White-type cell 4 transits

8. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Measured lines

9. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 III. Theoretical model

10. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Tensorial formalism Systematic expansion of effective Hamiltonian and transition moment up to any order and for any polyad scheme, thanks to group theory and tensorial methods  All interactions are automatically included  Vibrational extrapolation  Global analyses ParametersRotationVibration

11. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Effective Hamiltonian Operators V for the j polyad: {v 3 }, Γ 3 {v 2 }, Γ 2 {v 1 }, Γ 1 Hamiltonian for a j polyad: Energy Ground-state {0}, A g i Polyad with n i levels {v ni }, Γ ni j Polyad with n j levels {v nj }, Γ nj

12. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 IV. Band analysis and simulation

13. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Experiment / Simulation Black: White cell Red/green: 19.7 cm cell

14. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Experiment / Simulation Black: White cell Red: 19.7 cm cell

15. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Experiment / Simulation

16. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Experiment / Simulation Black: White cell Red: 19.7 cm cell

17. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Fit residuals: obs-calc for line positions

18. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Fit results: the tetrad region

19. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Fit results: the tetrad region (continued)

20. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 V. Perspectives for C 2 H 4 spectroscopy

21. 68th Ohio State University Symposium on Molecular Spectroscopy June 17–21, 2013 Perspectives Intensity analysis in the tetrad @ 10 μm Intensity analysis in the dyad @ 3 μm Global frequency and intensity analysis @ 10 and 3 μm Improvements in the 1.6 μm region