(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 FROM MATRIX ISOLATION SPECTROSCOPY TO FIRST OBSERVATION OF CO ISOTOPOLOGUE BAND IN THE ATMOSPHERE OF VENUS VENUS EXPRESS MISSION ESA PRODEX Program Contract C 90268

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 (1,5) P.R. Dahoo, Jean-Loup Bertaux, F. Montmessin, E. Villard (SA-France) FROM MATRIX ISOLATION SPECTROSCOPY TO FIRST OBSERVATION OF CO2 628 ISOTOPOLOGUE 2+ 3 BAND IN THE ATMOSPHERE OF VENUS (2) Ann Carine Vandaele, Valérie Wilquet, A. Mahieux ( IASB- Belgium) (3) O. Korablev, A. Fedorova & (4) V.I. Perevalov and S.A. Tashkun (IKI-IAO-Russia) ack:* G. L. Villanueva & Michael J. Mumma ( NASA -US)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 OBSERVING CO 2 ON VENUS FROM SPACECRAFT FROM MATRIX ISOLATION SPECTROSCOPY TO FIRST OBSERVATION OF CO2 628 ISOTOPOLOGUE 2+ 3 BAND IN THE ATMOSPHERE OF VENUS OBSERVING CO 2 IN A MATRIX ANALYZING OBSERVED SPECTRA PLAN OF THE TALK : 3 PARTS

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 OBSERVATION OF CO ISOTOPOLOGUE 2+ 3 BAND IN THE ATMOSPHERE OF VENUS PART 1: OBSERVING CO 2 ON VENUS FROM SPACECRAFT

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Interplanetary Transfer Orbit : Venus Express spacecraft From launch till Venus capture. FINAL OPERATIONAL ORBIT ON THE 7th MAY INSTRUMENTS ON BOARD SPICAV/SOIR

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPICAV on Venus Express SPICAV an ACRONYM for: SPectroscopy for the Investigation of the Characteristics of the Atmosphere of Venus Consists of three spectrometers in the UV and IR range with a total mass of 13.9 kg flying on the Venus Express (VEX) orbiter. Devoted to the study of the atmosphere of Venus from ground level to the outermost hydrogen corona at more than 40,000 km. (SPICAV P.I. JL BERTAUX)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPICAV Channels Ultraviolet (SUV)Infrared (SIR) SOIR Spectral range (µm) Spectral resolution0.8nm nm cm -1 Spectral resolving power (λ/Δλ) ~300~1300 ~ Field of View (rad)55 × / pixel SPICAV on Venus Express : Three spectrometers to study the global structure and composition of the Venus atmosphere Characteristics of the spectrometers

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 OBSERVATION PHASE: DIFFERENT MODES DEPENDS ON: 1) PAYLOAD CONFIGURATION & 2)SPACECRAFT ORIENTATION INCLUDES: Nadir pointing - preferably during pericentre pass, but possible on any portion of the orbit; VIRTIS, PFS, SPICAV and VMC may operate in this mode Limb observation - VIRTIS, PFS, SPICAV and VMC may operate in this mode Star occultation (SPICAV) &(SPICAV/SOIR) Radio science (VeRa)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 The SOIR spectrometer is a new solar occultation IR spectrometer in the range λ=2.2–4.3 μm, with a spectral resolution λ/Δλ>15,000, the highest on board VEX (IASB Contribution). Includes a combination of an echelle grating and an AOTF crystal to sort out one order at a time & array Detector. Simplified optical scheme of SOIR

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Top: red curve- spectrum A typical read-out, recorded in spectrometer order 133. Bottom: black – model of Earth atmosphere, green—CH4 only, blue— H2O only. Adopted resolving power for the synthetic spectra is 20,000. Comparison of Earth atmosphere transmission model with SOIR data for order 133 (TEST MODE ground base)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SOIR : Solar Occultation in the Infra Red. HOW ? VENUS ATMOSPHERE IS A HUGE ABSORPTION CELL WITH THE SUN AS LIGHT SOURCE FOR SPICAV- SOIR Programming a solar occultation means, VEX is oriented with Solar entry ports for all three spectrometers of SPICAV to the Sun. Solar spectra recorded by SOIR: first above the atmosphere then through the atmosphere

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPECTRUM OBSERVED IN THE 3 micron REGION 95 km to 70 km ASYMMETRIC SPECTRAL STRUCTURE ALWAYS OBSERVED NEAR 2982 cm -1 (120 km to 60 km) Bertaux, J.L., Vandaele, A.C., Wilquet, V., Montmessin, F., Dahoo, R., Villard, E., Korablev, O., Fedorova, A.,. Icarus 195 (1), 28–33 (2008).

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPECTROSCOPISTS INFORMAL DISCUSSION DATA BASES HITRAN : FAMOUS ONE THEORETICAL METHOD TO ANALYZE SPECTRUM EXPERIMENTAL CDSD: CO 2 GEISA OF COURSE BUT ALSO

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SEARCH FOR METHANE OR A CH BOND RESONANCE ABSORPTION POSSIBLE HCl SPECTRUM QUICKLY IDENTIFIED AND SIMULATED CO 2 WENT UNNOTICED FOR ABOUT 6 MONTHS FROM FIRST OBSERVATION

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 (A)All isotopologues of CO2, (B)The main isotopologue 12C16O16O, (C) 12C16O18O. Line parameters are from the CDSD-1000 database. The box delimits the wavenumber range for diffraction orders 132 and 133, and the thick line indicates the wavenumber range of the Transmission due to CO 2 calculated for a solar occultation through the Venus atmosphere Tangent height of 80 km Wilquet V, Mahieux A, Vandaele AC, Perevalov V, Tashkun S, Fedorova A, Montmessin, F., Dahoo, R., and Bertaux, J.L.,. JQSRT 109, 895–905 (2008)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPECTROSCOPY TO IDENTIFY CO ISOTOPOLOGUE NEXT STEP: SEEKING FOR EXPERIMENTAL DATA!! DATA BASES MISS OBSERVED TRANSITION

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SEEKING FOR EXPERIMENTAL DATA SPECTROSCOPY TO IDENTIFY CO ISOTOPOLOGUE PART 2: OBSERVING CO 2 IN A MATRIX

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 MATRIX ISOLATION TECHNIQUE MAINLY IMPULSED BY GEORGES PIMENTEL (1950) SPECTROSCOPIC STUDY UV-IR-MICRO WAVE ISOLATE IN INERT MATRIX AN UNSTABLE CHEMICAL SPECIES FOR SPECTROSCOPIC STUDY GAS MIXTURE COLD WINDOW SAMPLE SPECIES STABLE IN MATRIX GAS INLET (1 ) GAS INLET (2 ) KBr WINDOW SHIELD SAMPLE HOLDER PUMP SPECTROMETER

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 (M/R = 1000, T = 5 K, resolution = 0.15 cm −1 ) in the 2 bending and 3 stretching region (1 = stable site; 2 = unstable site) a = 626,b = 627, c = 628, d = 727, e = 728). ISOTOPOLOGUESISOTOPOLOGUES Infrared absorption spectrum of CO 2 in solid argon - Splitting of ν 2 mode in double site - 2 Trapping sites (S1 & S2) Dahoo, Teffo et al 1999

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SEEKING FOR EXPERIMENTAL DATA From recent work on CO 2 and matrix effect on isotopologues to identification of 628 absorption?

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 CONSTRAINT ON ROTATION THROUGH INTERACTION WITH MATRIX Potential energy of the trapped molecule-matrix system The vibrational part of the interaction potential dependence in terms of normal coordinates {Q} An orthogonal transformation is applied to the transformed Hamiltonian of the vibrating trapped molecule

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 CONTACT TRANSFORMATION [*] J. H. Van Vleck, Phys. Rev. 33, 467 (1929) [*]H. H. Nielsen, Phys. Rev. 60, 794 (1941); Rev. Mod. Phys. 23, 90 (1951) Compute energy levels by solving the resulting Schrödinger equation, using contact * transformation perturbation technique * as for gas phase (from the renormalized hamiltonian of the molecule in the matrix) Hψ=Eψ

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 VIBRATIONAL ENERGY LEVELS CALCULATIONS: NO ROTATION (EASIER) Don’t Forget RESONANCES !! DIAGONALIZING Dahoo et al: 2006

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Dahoo et al: 2006 CALCULATING VIBRATIONAL LEVELS OF CO ISOTOPOLOGUE ABSORPTION * J.L. TEFFO “SUPER” Ph.D Thesis (Doctorat D’Etat) 20/06/1990 Vibrational levels calculations of 628 match observation for band center SIMULATE VR Spectra WITH B, D and H

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 PART 3: ANALYZING SOIR SPECTRA FROM MATRIX ISOLATION SPECTROSCOPY TO IDENTIFICATION OF CO ISOTOPOLOGUE ABSORPTION AT 3.35 microns FINAL STEP

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 IR SPECTRUM : SELECTION RULES LINEAR MOLECULES : XYZ G. AMAT UPMC VIBRATION ROTATION SPECTRUM PERPENDICULAR BAND   

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE ) The feature located at 2982 cm ‑ 1 looks like a Q branch with R lines at higher and P lines at lower wavenumbers. OBSERVED SPECTRUM 2) They were located in the cm ‑ 1 spectral range, which correspond to four successive orders of diffraction of the instrument

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPECTROSCOPY TO IDENTIFY CO ISOTOPOLOGUE THIRD STEP: SPECTROSCOPISTS FOR THEORETICAL OR LABORATORY WORK FOR PRECISION

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 (A)Diffraction order 132: Regularly spaced P lines Q branch due to light pollution from adjacent order HCl lines present.( asterisk). Transmission due to CO 2 for a solar occultation through the Venus atmosphere Records of SOIR in the cm ‑ 1 spectral domain. Wilquet et al.. JQSRT 109, 895–905 (2008)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 (B) Diffraction order 133 Q branch & R lines HCl lines ( asterisk) Transmission due to CO 2 for a solar occultation through the Venus atmosphere Records of SOIR in the cm ‑ 1 spectral domain.

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 CACULATIONS BY S. TASHKUN (A)Diffraction order 132 SIMULATION Regularly spaced P lines & Lines due to HCl Wilquet V, Mahieux A, Vandaele AC, Perevalov V, Tashkun S, Fedorova A, Montmessin, F., Dahoo, R., and Bertaux, J.L.,. JQSRT 109, 895–905 (2008).

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 CACULATIONS BY S. TASHKUN (B) Diffraction order 133 SIMULATION Q branch & R lines Lines due to HCl Wilquet V, Mahieux A, Vandaele AC, Perevalov V, Tashkun S, Fedorova A, Montmessin, F., Dahoo, R., and Bertaux, J.L.,. JQSRT 109, 895–905 (2008).

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SAME IDENTIFICATION ON MARS For 628 & also for 638 and 627 G.J.Villanueva & M. Mumma et al. Icarus 195 (1)(2008) & J.Q..S.R.T. 109 (2008) 883–894

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 This spectral region is one of the prime search spaces for CH 4 (methane) and C 2 H 6 (ethane). The discovery of this 628 band is of high importance for assessing spectral confusion between these species. NIRSPEC spectra of the newly discovered band system of CO2 (628) on MARS. Geronimo L. Villanueva,, Michael J. Mumma, Robert E. Novak & Tilak Hewagama Icarus 195 (1)(2008), 34–44J.Q..S.R.T. 109 (2008) 883–894

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 HOW ABOUT 638? QUOTING: * The identification of the 2ν 1 band of 638 is tentative. Little is known about the vibrational structure of this isotope The upper vibrational state (20001) has not been catalogued in the literature. Rothman el al. ** report spectroscopic constants for the (Fermi resonant) vibrational level at Gv= cm −1. A Glance at band system of CO2 (638) identified on MARS. *Villanueva, G. L., Mumma, M. J., Novak, R. E., Hewagama, T. Icarus 195, 34–44 (2008) **JQSRT 48 (1992), pp. 537–566

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Two hypothesis by Villanueva et al. First hypothesis, the lines in the 2706–2720 cm −1 region correspond to the P-branch. BUT !! Expected R-branch lines in the 2730–2740 cm −1 region are not detected. NIRSPEC spectra of the newly discovered band system of CO2 (638) on MARS. Villanueva, G. L., Mumma, M. J., Novak, R. E., Hewagama, T. Icarus 195, 34–44 (2008)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Second hypothesis : detected lines correspond to the R-branch of the 638 2ν 1 band system. The band center is lower than 2706 cm −1. The intensity distribution peaks at 2710 cm −1, which for a column temperature of 207 K would mean a band center at cm −1. NIRSPEC spectra of the newly discovered band system of CO2 (638) on MARS. Villanueva, G. L., Mumma, M. J., Novak, R. E., Hewagama, T. Icarus 195, 34–44 (2008)

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 * J.L. TEFFO “SUPER” Ph.D Thesis (Doctorat D’Etat) 20/06/1990 NIRSPEC spectra of the newly discovered band system of CO2 (638) on MARS. CALCULATIONS FOR 638 * : cm : cm : cm -1 The intensity distribution peaks at 2710 cm −1, which for a column temperature of 207 K and the band center is at cm −1 (experimental). CONCLUSION

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 FUTURE OBSERVATIONS MARS EXPLORATION ON 2013 BY ESA SUBMISSION OF PROJECTS WELCOMED FROM EUROPE & FROM US TOO

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Professor G AMAT L HENRY A HENRY M MARGOTTIN THANKS TO OTHERS TOO!! LINEAR MOLECULES

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 OBSERVED & SIMULATED SPECTRUM THANK YOU FOR ATTENTION !!

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SPARE SLIDES

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SOIR AOTF Characteristics Wavelength (nm) Excitation frequency (MHz) Bandwidth (nm) Angular aperture (°) AOTF crystal.

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 The SOIR optics pass the filtered and dispersed light to a photo-voltaic MCT (HgCdTe) detector in an Integrated Detector Dewar Cooler Assembly (IDDCA). The detector is arranged as a 320×256 array of 30 μm square pixels. The IDDCA is equipped with a 0.4 Watt Stirling cycle rotary microcooler. With 4 grooves per mm the arctan(2) incidence-grating SOIR spectrometer operates on diffraction orders from 101 (4.4 μm) to 194 (2.3 μm). Echelle grating & Detector

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 SOIR AOTF Characteristics Wavelength (nm) Excitation frequency (MHz) Bandwidth (nm) Angular aperture (°) The SOIR optics pass the filtered and dispersed light to a photo-voltaic MCT (HgCdTe) detector contained in an Integrated Detector Dewar Cooler Assembly (IDDCA). The detector is arranged as a 320×256 array of 30 μm square pixels. The IDDCA is equipped with a 0.4 Watt Stirling cycle rotary microcooler.

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 EXPERIMENTAL RESULTS SPECTRUM SIMPLIFIED NO ROTATION OPTICAL THICKNESS FAVOURABLE FOR OBSERVATION BUT MATRIX DEPENDENT FEATURES FEW LINES - SHIFTED ONLY MOST INTENSE COLD BANDS ABSORBING REMARK! OBSERVATION OF OVERTONES AND COMBINATION BANDS FROM EMISSION (INDIRECT WAY) LASER INDUCED FLUORESCENCE

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 VIBRATIONAL LEVELS OF CO ISOTOPOLOGUE AND SELECTION RULES LABELLING OF LEVELS G. AMAT UPMC

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 IR SPECTRUM : SELECTION RULES VIBRATION ROTATION SPECTRUM ALLOWED TRANSITIONS LINEAR MOLECULES : XYZ PERPENDICULAR BAND    PARALLEL BAND    G. AMAT UPMC

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE ) WHAT ARE THE POSSIBLE TRAPPING SITES 3) HOW DOES THE MATRIX PERTURB THE ELECTRONIC POTENTIAL DRIVING THE VIBRATION OF THE NUCLEÏ 2) IN WHAT LATTICE (fcc, hcp, mixed..) QUESTIONS ? REQUIRES Modelling of matrix effect on vibrational energy states to calculate energy levels MODELLING ANALYSIS OF EXPERIMENTAL RESULTS MOST IMPORTANT

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 POTENTIAL ENERGY CO 2 /Ar MOLECULE IN MATRIX DOUBLE SITE C2 SYMMETRY AXIS NECESSARY TO MODEL MATRIX EFFECT ON OXIDES SINGLE SITE C4 SYMMETRY AXIS MOLECULE IN MATRIX DOUBLE SITE C2 SYMMETRY AXIS NECESSARY TO MODEL MATRIX EFFECT ON OXIDES SINGLE SITE C4 SYMMETRY AXIS MOLECULE IN MATRIX DOUBLE SITE C2 SYMMETRY AXIS NECESSARY TO MODEL MATRIX EFFECT ON OXIDES SINGLE SITE C4 SYMMETRY AXIS MOLECULE IN MATRIX DOUBLE SITE C2 SYMMETRY AXIS NECESSARY TO MODEL MATRIX EFFECT ON OXIDES SINGLE SITE C4 SYMMETRY AXIS Energy (cm -1 )   Double Site C 2 CO 2 : Ar- 2 SITES (Single and Double) Kr et Xe -1 SITE (Single) fcc Lattice

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 The Born-Oppenheimer approximations Vibrational energy levels of a molecule trapped in a RG matrix? The eïgen values of the Schrödinger equation for the molecular system coupled to the matrix. [*] J. H. Van Vleck, Phys. Rev. 33, 467 (1929) [*]H. H. Nielsen, Phys. Rev. 60, 794 (1941); Rev. Mod. Phys. 23, 90 (1951) In gas phase: apply Born-Oppenheimer approximation, the nuclei being assumed to be moving in the mean potential due to the rapidly moving electrons. Interaction with the matrix implies this potential is perturbed & small shifts are induced on the vibrational levels of the embedded molecule Compute energy levels by solving the resulting Schrödinger equation, using contact * transformation perturbation technique * as for gas phase (from the renormalized hamiltonian of the molecule in the matrix) Hψ=Eψ

(5) (1) (2) (4) (3) P.R.DAHOO et al. JUNE 2008 Cal-Exp Results: IR Fluo SPECTROSCOPY OF CO 2 /Ar Emissions fluorescence: 10 (1) and 16 (3) microns PhD Thesis Chabbi (2000)