Transcript CH4.pptx
HIGH RESOLUTION SPECTROSCOPY AND GLOBAL ANALYSIS OF THE TETRADECAD REGION OF METHANE 12CH4 A. NIKITIN, Institute of Atmospheric Optics, 634055 Tomsk, Russia and Laboratoire GSMA, UMR 6089 CNRS-Universit´e de Reims Champagne Ardenne, Moulin de la Housse BP 1039, Cases 16-17, F-51687 Reims Cedex 2, France; V. BOUDON, C. WENGER, Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS-Universit´e de Bourgogne, 9. Av. A. Savary, BP 47870, F-21078 Dijon Cedex, France; L. R. BROWN, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA; S. BAUERECKER, Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland and Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, D-38106, Germany; S. ALBERT, M. QUACK, Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland. 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Contents I. The polyads of CH4 II. Analysis of line positions III. Analysis of line intensities IV. Conclusions and perspectives 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 I. The polyads of methane 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Global fit The polyads of methane 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 The Tetradecad vibrational sublevels 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 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 H Pk t K ,n v v ' ss ' all indexes K ,n v v ' (A1g ) R Vss ' Parameters Rotation Vibration All interactions are automatically included Vibrational extrapolation Global analyses 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 II. Analysis of line positions 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Tetradecad analysis • Starting point: 0–4800 cm-1 global analysis up to Octad: Albert et al., Chem. Phys. 356, 131–146 (2009) and HITRAN 2008 • Improved analysis (although still preliminary) by Andrei Nikitin with MIRS • Parameter translation to STDS • STDS improvements (fit procedure, higher order vibrational terms included) • Global fit: 0 – 6200 cm-1 with STDS • Paper to be submitted 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Fit details H GS, H Dyad, H Pentad, H Octad, H Tetradecad expanded to order 6, 6, 5, 5, 5, respectively Number of parameters, ( ) = fitted Order H GS Tetradecad H Dyad Tetradecad H Pentad Tetradecad H Octad Tetradecad H Tetradecad Tetradecad H Tetradecad 0 1 (1) 2 (2) 2 (2) 0 (0) 0 (0) 5 (5) 1 0 (0) 2 (2) 5 (5) 0 (0) 0 (0) 7 (7) 2 2 (2) 6 (6) 21 (20) 13 (9) 7 (7) 49 (44) 3 0 (0) 6 (6) 35 (35) 57 (48) 36 (29) 134 (118) 4 3 (3) 13 (13) 71 (65) 183 (147) 219 (113) 489 (341) 5 0 (0) 11 (9) 94 (82) 342 (274) 672 (113) 1120 (484) 6 4 (4) 22 (20) 0 (0) 0 (0) 0 (0) 26 (24) Total 10 (10) 62 (53) 228 (209) 596 (478) 896 (747) 1830 (1023) Total: 19747 data (MW, IR, Raman) Tetradecad dRMS = 23 10 3 cm 1 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Residuals for line positions The octad is slightly worse than in Albert et al. (but still OK) 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Residuals for line positions 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Calculated levels and mixings 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Observed levels and mixings 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 III. Analysis of line intensities 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Octad test 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Residuals for line intensities 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Global comparison at 296 K 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Global comparison at 80 K 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Comparison for 4ν4 at 296 K 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Comparison for 4ν4 at 78 K 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 IV. Conclusions and perspectives 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 CH4 Spectroscopy: what next? • Continue the « global fit » approach • Tetradecad much better but still to improve • Add new data (positions, intensities, hot bands) • Icosad, … • CH4 “windows” (high J, far wings) • Hot methane (combustions, brown dwarfs, hot jupiters, …) Titan / Cassini-Huygens Huygens DISR spectra Brown dwarf Gliese 229 B / HST 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011 Virtual Atomic and Molecular Data Center http://vamdc.icb.cnrs.fr/PHP/methane.php 66th Ohio State University Symposium on Molecular Spectroscopy • June 20–24, 2011