High-Resolution Spectroscopy and Analysis of the n3/2n4 Dyad of CF4 Vincent BOUDON Institut Carnot de Bourgogne – UMR 5209 CNRS-Université de Bourgogne, 9 Av. A. Savary, BP 47870, F-21078 DIJON, France Alexandra DOMANSKAYA Institute of Physics, Saint Petersbourg University, 198504, SAINT PETERSBOURG, Russia Christof MAUL Institut für Physikalische un Theoretische Chemie des Technischen Universität Braunschweig, D-38106 BRAUNSCHWEIG, Germany Robert GEORGES Institut de Physique de Rennes, UMR 6251 CNRS – Université de Rennes 1, 263 Av. Général Leclerc, F-35042 RENNES, France Justin MITCHELL Department of Physics, University of Arkansas, FAYETTEVILLE, USA
The CF4 molecule CF4 is a strong greenhouse gas (natural and anthropogenic origin) Global Warming Potential = 6500 (CO2 = 1), lifetime = 50,000 years Concentration = 75 pptv, annual increase = 1.6 % 1 2 3 4 A1 E F2 Stretching Bending Raman IR 909 cm-1 435 cm-1 1283 cm-1 631 cm-1 Point group Td
Contents Experimental details Theory Simultaneous analysis of line positions Intensities Semi-classical study
I. Experimental details
Data used for the simultaneous fit Static-cell spectra (Braunschweig and Rennes) Supersonic expansion jet spectrum (Rennes) MW data for n3–n3 (M. Takami et al., Mol. Phys. 85, 733–744 (1995))
II. Theory
Effective tensorial Hamiltonian Polyad structure P0 P1 P2 Systematic tensorial development Coupled rovibrational basis Effective Hamiltonian and vibrational extrapolation
Effective Hamiltonian for CF4 Effective Hamiltonian for the Ground State (P0 polyad) Effective Hamiltonian for the v4 = 1 level (= P1 polyad) Effective Hamiltonian for v4 = 2 / v3 = 1 (= P2) polyad
III. Simultaneous analysis of line positions
Fit statistics
Overview of the n4 band
Detail in the n4 band
n4 band : fit residuals for line positions
The 2n4 band
Overview of the n3 band
Jet-cooled spectrum of the n3 band
n3/2n4 dyad: fit residuals for line positions
IV. Intensities
Dipole moment parameters Fit of the proportionality coefficient between the experimental and simulated spectrum to find the dipole moment derivatives n4 : use of P and R branches n3 : R branch only, P branch is perturbed by 2n4 Rough estimation for 2n4
V. Semi-classical study
Semi-classical energy curves
Semi-classical vs. quantum levels See talk RJ06
Spherical Top Data System The STDS database Spherical Top Data System www.icb.cnrs.fr/OMR/SMA/SHTDS • Molecular parameter database • Calculation and analysis programs • XTDS : Java interface NB : CF4 results included in HITRAN 2008