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PI-12

B. V. Perevalov, S. Kassi , and A. Campargue High sensitivity CW-CRDS spectroscopy of the eight most abundant CO2 isotopologues between 5851 and 7045 cm-1 Critical review of the current databases B. V. Perevalov, S. Kassi , and A. Campargue Laboratoire de Spectrométrie Physique, CNRS Université Joseph Fourier de Grenoble, France V. I. Perevalov , S. A. Tashkun IAO Tomsk, Russia

I.- The CW-CRDS spectrometer with DFB lasers in the 1.4-1.7 mm range

Cavity Ring Down Sectroscopy Laser output T OFF time I output ON Ring Down ! (1 à 200 µs) OFF Laser 

Cavity Ring Down T T - empty cell - with gaz t t0 Absorption losses Laser output T Absorption losses time Intensity - empty cell t - with gaz t0

Cavity Ring Down T T Laser output Spectrum Wavelength scan Ring down variation of the Ring down

PI-08

A compact CW-CRDS spectrometer (S. Kassi, D A compact CW-CRDS spectrometer (S. Kassi, D. Romanini) 1480-1700 nm (5940-7030 cm-1) 6nm/diode 40 diodes Lambdameter Laser diode n=f(T,I) Optical isolator Coupler -50 50 100 threshold Laser OFF AO Modulator laser ON Photodiode

“routine” CW-CRDS (8000) - 7000 - 5850 cm-1 Spectral coverage: (1250) - 1428 -1705 nm (8000) - 7000 - 5850 cm-1 Typical noise level: amin~3×10-10 cm-1 1 % intensity attenuation after 300 km High dynamics: absorption coefficients from 10-5 to 10-9 cm-1 are measured on a single spectrum. Doppler limited resolution Wavenumber accuracy is about 0.001 cm-1

Illustration of the achieved sensitivity: The example of the a1Δg(0)−X3Sg(1) of O2 k=8×10-31cm/molec =2×10-11cm 1 % absorbance after 5000 km Chem. Phys. Lett. 409 (2005) 281–287

the third dimension of an absorption spectrum Sensitivity: the third dimension of an absorption spectrum

636 HITRAN

636 11121-00000

636

II. Line intensity measurements:

636

636 PI-O6

III. Rovibrational analysis About 10 lines observed/cm-1: Hot bands up to Elow=3004 cm-1 relative concentration of 5×10-7 Minor isotopologues 828: 3.9×10-6 Impurities (the cell has a good memory!!)

Natural isotopic abundance of CO2 molecule 626 0.98420 636 0.01106 628 0.0039471 627 0.000734 638 0.00004434 637 0.00000825 828 0.0000039573

typical rms values of the residuals ~ 1x10-3 cm-1 band-by-band analysis of 121 and 117 bands for 12C and 13C isotopologues respectively typical rms values of the residuals ~ 1x10-3 cm-1

Effective Hamiltonian Model S. A. Tashkun, V. I. Perevalov, J. –L. Teffo 1388 cm-1 667 cm-1 2349 cm-1 } Our spectral region corresponds to DP= 9 We observe transitions reaching P=10-13 polyads with Eup up to 9900 cm-1

Excellent agreement with CDSD However, significant deviations new fit of the EH parameters 626: JMS 230 (2005) 1–21 636: JMS 226 (2004) 146–160 637 and 638: JMS 241 (2007) 90–100 rms=4.2 ×10-3 cm-1 Intrapolyad interactions are accurately predicted and reproduced by the EH model rms=2.7 ×10-3 cm-1

Newly evidenced interpolyad anharmonic interaction: in 638 (2 occurences), 637 (1) and 628 (1) Example: 638: 31113 (P=10) ↔51106 (P= 11)

628 626

IV. Comparison with the current CO2 databases

626 bands lines 4x10-27 28 1903 1x10-26 18 816 4x10-30 50 6210 3x10-29 94 5604 CDSD (4x10-30) 164 13225

pure 636 4x10-25 1x10-25 4x10-28 3x10-29 bands lines 8 774 8 259 18 1694 3x10-29 104 4881

Line positions comparison 626 HITRAN-CRDS GEISA-CRDS HITEMP-CRDS

626 JPL-CRDS JPL-CDSD CDSD-CRDS

628 JPL-CRDS JPL-CDSD CDSD-CRDS

636 JPL-CRDS

626 Line intensities comparison

pure 636

V. Conclusion The 12CO2 and 13CO2 spectra wer recorded in the 5841–7045 cm-1 region with a typical sensitivity of 3×10-10 cm-1. The dynamic on the line intensities is from 10-24 to 3x10-29 cm/molecule. 16932 lines were assigned to 280 bands of 8 isotopologues of CO2. Our data have allowed a significant improvement of the EHs and EDMs of CDSD

Present HITRAN Advantages Drawbacks Complete above 4x10-27 Not sensitive Deviations<0.02 cm-1

Present HITRAN JPL Advantages Drawbacks Complete above 4x10-27 Not sensitive Deviations<0.02 cm-1 JPL Very accurate observations for the strongest bands Pressure shifts and self and air broadening coefficients Incomplete Too long range extrapolation (4x10-30) Some very large deviations Traceability

Present HITRAN JPL CRDS Advantages Drawbacks Complete above 4x10-27 Not sensitive Deviations<0.02 cm-1 JPL Very accurate observations for the strongest bands Pressure shifts and self and air broadening coefficients Incomplete Too long range extrapolation (4x10-30) Some very large deviations Traceability CRDS Nearly complete above 5x10-29 Typical accuracy 1x10-3 cm-1 (1250) - 1428 -1705 nm (8000) - 7000 - 5850 cm-1

Present HITRAN JPL CRDS CDSD Advantages Drawbacks Complete above 4x10-27 Not sensitive Deviations<0.02 cm-1 JPL Very accurate observations for the strongest bands Pressure shifts and self and air broadening coefficients Incomplete Too long range extrapolation (4x10-30) Some very large deviations Traceability CRDS Nearly complete above 5x10-29 Typical accuracy 1x10-3 cm-1 (1250) - 1428 -1705 nm (8000) - 7000 - 5850 cm-1 CDSD Complete (at least for 626, 636 and 628) Excellent predictive abilities for positions and intensities Interpolyad coupling Cannot reproduce JPL accuracy A factor of 2 worse than the CRDS accuracy for line centers of the weak bands

CH4 (PI-12) N2O 16O3 (III-4), 18O3 (PI-8) C2H2 NO2 Our CW-CRDS spectrometer has allowed similar investigations for: H2O, H218O, HDO CH4 (PI-12) N2O 16O3 (III-4), 18O3 (PI-8) C2H2 NO2

Merci

12CO2 HITRAN JPL database CRDS Bands Lines 626 28 1903 50(18) 6210(816) 94 5604 628 7 467 15(3) 2713(179) 25 1922 627 3 159 6 1017 11 767 Total 38 2529 71(21) 9940(995) 130 8293

13CO2 HITRAN JPL database This work Bands Lines 636 8 774 18 (8) 1694 (259) 104 4881 638 4 (1) 446 (55) 28 2466 637 2 (0) 184 (0) 11 992 838 0 (0) 4 170 738 3 130 Total 24 (9) 2324 (314) 150 8639