TE06MatthewCichOhio2011.ppt
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Transcript TE06MatthewCichOhio2011.ppt
Frequency Comb-Referenced
Measurements of Self- and
Nitrogen- Perturbed Line Shapes in
the ν1+ν3 Band of Acetylene
Matthew Cich
Stony Brook University
June 21, 2011
Support: Department of Energy Basic Energy Sciences and EPSCoR,
ACS, PRF New Directions, NASA Planetary and Atmospheres program
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Introduction
Frequency combs allow for very high resolution measurements
C2H2, P(11) of ν1+ν3
Line center = 195739.6495135(80) GHz, (~6529 cm-1)
Self- and N2-broadening
experiments
• T=296 K
• Three line shape models
(Rautian, Galatry, Voigt)
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Frequency comb
(Not to scale)
•Each comb line: ωn=nωr+ω0
•CW laser locked to nearest comb line (approx. n=790,000)
•Scan ωr by Hz to move CW laser hundreds of kHz
•CW laser frequency accuracy ~1011
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Experimental details
•Line shape models: Voigt, Rautian (Hard), Galatry (Soft)
•Lifetime broadening γ, line shift δ, Dicke narrowing β
•β is related to Friction Coefficient through gas diffusion
Data Collection
Gaussian Raw Data (0.16 torr)
Pure C2H2 at 155 Torr
N2-Perturbed, 1.26% C2H2 at 54 Torr
Data analysis results
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Parameter comparison
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Benefits of frequency combs in line
shape studies
• Improved accuracy in line shape parameters
• Distinction between similar line shape models
• Determine how models relate to the physics of
the system
Acknowledgements
Gary Lopez
Stony Brook University
Trevor Sears
Brookhaven National Laboratory
Stony Brook University
Christopher McRaven
Brookhaven National Laboratory
Arlan Mantz
Connecticut College
Daniel Hurtmans (not shown)
Universite Libre de Bruxelles
Parameter comparison-N2
Broadening (γN2)
Narrowing (βN2)
Shift (δN2)
Hard
0.081129(35)
0.022939(74)
-0.0088913(25)
Soft
0.083217(37)
0.034611(99)
-0.0088973(25)
Voigt
0.068979(33)
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-0.0088663(48)
Voigt [1]
0.0805(8)
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-0.0085(1)
Voigt (P22 line)[2]
0.065(1)
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-0.0082(2)
All units are cm-1/atm, error is one standard deviation.
[1]S.W. Arteaga, C.M. Bejger, J.L. Gerecke, J.L. Hardwick, Z.T. Martin, J. Mayo, E.A.
McIlhattan, J.-M.F. Moreau, M.J. Pilkenton, M.J. Polston, B.T. Robertson, E.N.
Wolf, J. Molec. Spectrosc. 243 (2007) 253–266.
[2] P. Minutolo, C. Corsi, F. D’Amato, M. DeRosa, Eur. Phys. J. D 17 (2001) 175–179.