1. Cavity Ring-down Spectroscopy Of Hydrogen In The nm Region And Corresponding Line Shape Implementation Into HITRAN
Yan Tan (a,b), Jin Wang (a), Cun-Feng Cheng (a), An-Wen Liu (a), Shui-Ming Hu (a), P. Wcislo (b,c), R.V Kochanov (b,d), I.E. Gordon (b), L.S. Rothman (b)
(a)Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China; (b) Atomic and Molecular Physics Division , Harvard-Smithsonian Center for Astrophysics, USA; (c) Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Poland;(d)Laboratory of Quantum Mechanics of Molecules and Radiative Processes, Tomsk State University, Russia
University of Science and Technology of China

2. S Q O Cavity Ring-down Spectroscopy Of Hydrogen J
Most abundant molecule in universe
Most fundamental neutral molecule
Unique molecule – line shape study
Homonuclear diatomic molecule p o 1 2 3 J S Q O
nm n=3-0

3. CW Cavity Ring-down System
Cavity Ring-down Spectroscopy Of Hydrogen
CW Cavity Ring-down System
OFF
time
Iout ON
Ring Down !
I =I0 exp(-t/τ) In
Out
OFF
Laser
Ring-down Cavity
Laser
Pump
AOM
Trigger
ULE Etalon
DAQ PD
PZT

4. Cavity Ring-down Spectroscopy Of Hydrogen
Ultrahigh sensitivity
Equivalent absorption path length
Leff ≈ L/(1-R), Leff ~102 km
High frequency accuracy
Calibrated with atomic lines, <2MHz In
Out L R

5. Good signal-to-noise ratio for accuracy value
Cavity Ring-down Spectroscopy Of Hydrogen
Good signal-to-noise ratio for accuracy value
V=30, J=75
Line intensity: 9.2×10-31 cm/molecule
at 296 K
H2, Q(1)
Galatry:rms~2.6×10-11 cm-1

6. Cavity Ring-down Spectroscopy Of Hydrogen
Positions and intensities for the transitions of (3 - 0) H2 band measured by CRDS

7. Cavity Ring-down Spectroscopy Of Hydrogen
Line position and intensity determination
: 3X10-4cm-1
: -1%
Calculation from Pachucki et al., Phys. Rev. A 83,  

8. Corresponding Line Shape Implementation Into HITRAN
Experimental data
analysis
implementation
OF-CEAS high-pressure Raman
spectra (1-0)
CRDS spectra [in Grenoble] (2-0)
Our work : CRDS spectra (3-0)
HITRAN Application Programming
Interface (HAPI)
New HITRAN online
non-Voigt
profile
HTP (Hartmann-Tran profile)
quadratic speed dependence + hard-collisions model
P. Wcisło, et al. , J Quant Spectrosc Radiat Transf, 177, 75-91(2016)

9. Corresponding Line Shape Implementation Into HITRAN
3-0 S(1) line

10. Corresponding Line Shape Implementation Into HITRAN
The results of the OF-CEAS and the CRDS spectra analysis for the (1-0), (2-0) and (3-0) bands:

11. Corresponding Line Shape Implementation Into HITRAN
From HITRANonline:
New Output Format
Parameter Units C|Fortran
Format

12. Corresponding Line Shape Implementation Into HITRAN
Profile
Function name
Parameters
Voigt
PROFILE_VOIGT
GD, G0, D0
Speed-dependent Voigt
PROFILE_SDVOIGT
GD, G0, G2, D0, D2,
Rautian
PROFILE_RAUTIAN
GD, G0, D0, nVC
Speed-dependent Rautian
PROFILE_SDRAUTIAN
GD, G0, G2, D0, D2, nVC
Hartmann-Tran
PROFILE_HT
GD, G0, G2, D0, D2, nVC, h
Sample spectra by using HAPI to simulate the absorption coefficient of H2 1-0 band
Presentation by Roman, “ HITRAN APPLICATION PROGRAMMING INTERFACE (HAPI): EXTENDING HITRAN CAPABILITIES”
Tuesday, TG12 : P1951
R.V. Kochanov, et al. , J Quant Spectrosc Radiat Transf, 177, 15-30(2016)

13. Summary and Outlook For experiments: For HITRANonline Have done:
High precision measurement of ro-vibrational transitions of H2
These spectroscopy data along with others have been reanalyzed as a test for non-Voigt profile to HITRAN database
For experiments:
Calibration with combs : toward sub-ppb (0.1MHz)
Thermo-stabilized (1mK) sample cell : toward a determination of kB
For HITRANonline
Successfully tested the Hartman-Tran profile : more measurements for other molecules
Keep on updating the database :
Introducing line-mixing effect: CH4

14. Acknowledgements
Thanks for the help of our former group members ( Shui-Ming Hu, An-Wen Liu,
Jin Wang and many others…).
Also thanks for the help of our HITRAN group members (Laurence Rothman, Iouli Gordon, Roman Kochanov …).
University of Science and Technology of China
HITRANonline:

15. Thanks for your attention!
University of Science and Technology of China