New 12 C 2 H 2 measurements using synchrotron SOLEIL David Jacquemart, Nelly Lacome, Olivier Piralli 66th OSU international symposium on molecular spectroscopy 2011 – WF08

FTS (Bruker 125HR) and synchrotron source around 100 µm (100 cm -1 ) → HERSHEL space observatory – instrument PACS (up to 160 cm -1 ) In Saint-Aubin located at a few kilometers from Paris → Use of synchrotron source SOLEIL (AILES beamline) 66th OSU international symposium on molecular spectroscopy 2011 – WF08

Experimental conditions for 2010 SOLEIL spectra → Use of a multispectrum fitting procedure to retrieve line positions and intensities with a Voigt profile

66th OSU international symposium on molecular spectroscopy 2011 – WF08

Water transitions Acetylene from Kabbadj et al. 66th OSU international symposium on molecular spectroscopy 2011 – WF08

In 2010, using 150 m absorption path: P(C 2 H 2 )= 0.25, 0.6, 2, and 5 mbar 66th OSU international symposium on molecular spectroscopy 2011 – WF08

Michelson-type Interferometer Limitation of the optical path difference Recent progress in acetylene laboratory measurements for astrophysical applications, EGU General Assembly 3-8 April 2011

Effects of the size of the beam I’ (  )   sin (  0   / 2) / (  0   / 2)   cos [2   0  (1   /4  )] Shift of the positions to lower wavenumbers of a quantity equal to  0  /4  Optical weighting of the rectangular function (boxcar) Apodization of the sin c 66th OSU international symposium on molecular spectroscopy 2011 – WF08

Classical source (globar…) Radius of the beam delimited by an iris. The size of the beam in the interferometer is a constant physical parameter. Synchrotron source (AILES) Radius of the beam not delimited by an iris. The size of the beam in the interferometer is depending on the photons energies. (SOLEMIO and SRW models)  At 10 cm -1, diameter of 7 mm  At 100 cm -1, diameter of 2.5 mm  At 1000 cm -1, diameter of 0.8 mm The size of the beam is known (even if slight differences from diffraction effects). The optical weighting is wavenumber dependent ! 66th OSU international symposium on molecular spectroscopy 2011 – WF08 The size of the beam is not constant according to wavenumbers. The optical weighting is almost constant according to wavenumbers.

66th OSU international symposium on molecular spectroscopy 2011 – WF SOLEIL spectra Effective iris radius from line by fine fitting (H 2 16 O in open symbols and 12 C 2 H 2 in solid ones)

66th OSU international symposium on molecular spectroscopy 2011 – WF SOLEIL spectra Effective iris radius from line by fine fitting (H 2 16 O in red symbols and 12 C 2 H 2 in black ones)

66th OSU international symposium on molecular spectroscopy 2011 – WF SOLEIL spectra Effective iris radius from line by fine fitting (H 2 16 O in red symbols and 12 C 2 H 2 in black ones)

66th OSU international symposium on molecular spectroscopy 2011 – WF SOLEIL spectra Effective iris radius from line by fine fitting (H 2 16 O in red symbols and 12 C 2 H 2 in black ones)

66th OSU international symposium on molecular spectroscopy 2011 – WF SOLEIL spectra Effective iris radius from line by fine fitting (H 2 16 O in red symbols and 12 C 2 H 2 in black ones)

66th OSU international symposium on molecular spectroscopy 2011 – WF SOLEIL spectra Effective iris radius from line by fine fitting (H 2 16 O in red symbols and 12 C 2 H 2 in black ones) Spectrum #0 recorded using iris radius = 0.9 mm

66th OSU international symposium on molecular spectroscopy 2011 – WF08 Wavenumber calibration using H 2 O transitions (open circles in spectrum #0, open squares in #1, solid squares in # 2, solid triangles in # 3 and open triangles in #4) and NH 3 transitions (open stars in spectrum #1)

66th OSU international symposium on molecular spectroscopy 2011 – WF08 Transition dipole moment for the band [Amy10] Amyay B., Herman M., Fayt A., Fusina L, Predoi-Cross A.. Chemical Physics Letters 491:17 (2010). [JAC10] Jacquemart D., Gomez L., Lacome N., Mandin J.-Y., Pirali O., Roy P. JQSRT 111, (2010).

66th OSU international symposium on molecular spectroscopy 2011 – WF08 Transition dipole moment for the ( ) band

66th OSU international symposium on molecular spectroscopy 2011 – WF08 Transition dipole moment for the ( ) band (forbidden band with ∆ℓ=2)

66th OSU international symposium on molecular spectroscopy 2011 – WF08 Transition dipole moment for the ( ) 0 + band

Conclusion - Better signal to noise ratio in 2010 than in 2009 (mainly due to the bolometer) - Smaller dispersion of the radius of the beam (more accurate model of apparatus function) - Absolute line positions and intensities retrievals ( for 816 transitions belonging to 17 bands between 51 and 215 cm - 1 ) 66th OSU international symposium on molecular spectroscopy 2011 – WF08

Thank you for your attention 66th OSU international symposium on molecular spectroscopy 2011 – WF08

Kabbadj Y, Herman M, Di Lonardo G, Fusina L, Johns JWC. JMS 150:535 (1991) SOLEIL-AILES(2009) D. Jacquemart, L. Gomez, N. Lacome, J.-Y. Mandin, O. Pirali, P. Roy, JQSRT 110: 2102 (2009) SOLEIL-AILES (2009) White cell with 10m absorption path, pressure of acetylene between 0.5 – 10 mbar ( cm -1 ) 10 bands observed, Line intensities retrievals for the strongest ν 5 – ν 4 band B. Amyay, M. Herman, A. Fayt, L. Fusina, A. Predoi-Cross. Chemical Physics Letters 491:17 (2010) Canadian Light Source, Saskatoon White cell with 72m absorption path, pressure of acetylene between 1 – 4 mbar (46-246cm -1 ) 20 bands observed positions and intensities calculation ( constant vibrational dipole moment ) D. Jacquemart, N. Lacome, O. Pirrali. (to be submitted) SOLEIL-AILES (2010) White cell with 150m absorption path, pressure of acetylene between 0.1 – 10 mbar ( cm-1) bands observed, Line intensities retrievals for at least 15 weak bands (to be submitted) One FT spectrum res = cm -1 White cell with 18m absorption path Pa 10 bands observed, Line positions analysis