11 The THz spectrum of GlycolAldehyde M. Goubet, T.R. Huet, I. Haykal, L. Margulès PhLAM, CNRS –...
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1 The THz spectrum of GlycolAldehyde M. Goubet , T.R. Huet, I. Haykal, L. Margul PhLAM, CNRS – Université de Lille 1 O. Pirali, P. Roy AILES beamline, synchrotron SOLEIL OSU ISMS – June 20-24 2011 Laboratoire de Physique des Lasers, Atomes et Molécules Tél. +33 (0)320 434785 | Fax. +33 (0) 320 337020 www-phlam.univ-lille1.fr
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Transcript of 11 The THz spectrum of GlycolAldehyde M. Goubet, T.R. Huet, I. Haykal, L. Margulès PhLAM, CNRS –...
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The THz spectrumof GlycolAldehyde
M. Goubet, T.R. Huet, I. Haykal, L. MargulèsPhLAM, CNRS – Université de Lille 1
O. Pirali, P. RoyAILES beamline, synchrotron SOLEIL
OSU ISMS – June 20-24 2011
Laboratoire de Physique des Lasers, Atomes et MoléculesTél. +33 (0)320 434785 | Fax. +33 (0) 320 337020 www-phlam.univ-lille1.fr
2
stable isomers of the chemical formula C2H4O2
GlycolAldehyde (GA)detected in the ISM
prebiotic molecule (simpliest sugar)
Acetic Acid (AA)detected in the ISM
various industrial apps (most abundant carboxylic acid): polymers, drugs, food ads, solvents
MethylFormate (MF)detected in the ISM
few industrial apps (harmful and flammable):
insecticide, drugs, refrigerant
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
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Astrophysical interestRegions of characteristic
signals of COMs
Support to space
observation missions
(Herschel, Alma, …)
Inaccurate extrapolations
from mm-waves
Spectroscopic interestLarge amplitude motions and intermolecular modes are in the FIR
Low excitation energy = non-destructive probing
access to the dynamic, conformational and structural properties.
Why from the mm-waves to FIR regions ?
MF - 18O spectrum @ 100 K
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
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The GA spectrum: background
No FIR spectrum of GA (dimeric powder in standard conditions)
C-C torsion (1) ~ 200 cm-1 (very weak)
C-C-O bend (2) ~ 300 cm-1 (weak)
C-OH torsion (3) ~ 370 cm-1 (medium)+ hot and combination bands
M. L. Senent, J. Phys. Chem. A 108 (2004) 6286
Previous studies in the cm-, mm- and submm-waves regions:
M. Rey et al., Chem. Phys. Lett. 430 (2006) 121.
K.-M. Marstokk et al., J. Mol. Struct. 5 (1970) 205.
R.A.H. Butler et al., ApJS 134 (2001) 319.
S.L. Widicus-Weaver et al., ApJS 158 (2005) 188.
P.B. Carroll et al., ApJ 723 (2010) 845.
global fit including all dataThe THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
55
The GA spectrum: new data in the THz region
The rQ branch(J~55, Ka=36)
P = 0.030 mbar,
T = 294 K,
780 – 950 GHz region.
The Lille spectrometer
See talks: FA07 – FA08 – FA09
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
66
Data in the 2-1300 GHz range from Lille/Oslo/Columbus/JPLfitted at the experimental accuracy:Parameter
This Work Caroll et al Parameter
This Work Caroll et al
A 18446.26463(24)
18446.25696(134)
J x 109 -7.200(16) -7.710(170)
B 6525.998019(86)
6525.99578(51) JK x 109 172.47(18) 170.86(168)
C 4969.235650(91)
4969.23452(50) KJ x 109 -811.39(46) -825.6(57)
J x 103 6.221459(58) 6.21986(47) K x 109 1076.37(77) 1060.9(65)
JK x 103 -20.38811(33) -20.39838(219) J x 109 -2.1338(21) -2.2752(253)
K x 103 47.71178(68) 47.6959(36) JK x 109 -26.139(91) -25.42(105)
J x 103 1.834568(12) 1.833997(112) K x 109 286.3(12) 309.6(174)
K x 103 8.86289(31) 8.8676(45) LJ x 1012 0.335(13) 0.0776(222)
Jmax 80 63 LJJK x 1012 -0.358(26) 0.211(203)
Kmax 37 32 LJK x 1012 -4.009(74) -3.90(65)
N of Lines
3848 1412 LKKJ x 1012 22.07(18) 26.65(154)
Fit rms 0.043 0.061 LK x 1012 -28.52(31) -21.82(252)
Ground state parameters (in MHz)
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
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Data in the 2-950 GHz range from Lille/Oslo/Columbus/JPLfitted at the experimental accuracy:
Excited states results
1 2 3
This work
previousThis work
previousThis work
previous
Jmax 77 61 76 48 76 39
Kmax 35 14 35 15 32 15
N of Lines
2221 672 2065 491 1882 340
Fit RMS(MHz)
0.052 0.130 0.053 0.129 0.054 0.120
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
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The GA spectrum: new data in the FIR
(Soleil SR + IFS125HR + long pass cell)
@ Ailes beamline:
High brightness in the FIR: less scans needed
White type multipass cell: absorption length = 150 m
High sensitivity for low vapor pressure samples.
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
100 200 300 400 500 6000
2
4
6
8
10
12
14
16
18 S/N enhancement for measurement through 150 m cell @ 0.001 cm-1 resolution:Synchrotron vs lab. source
Ra
tio
of
S/N
SR
vs
La
b. S
ou
rce
s
Wavenumber (cm-1)
99
The GA spectrum: new data in the FIR
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
3 (1←0)
3 (2←1)
2 (1←0)
1 (1←0)
1 (2←1)
1 (3←2)
1-3 (?←?)
HR (10-3 cm-1) spectrum of GA (< 10-2 mb)@ AILES – long pass (150 m) cell
1010
The GA spectrum: new data in the FIR
Wavenumber / cm-1
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
1111
1 (1←0) 2 (1←0) 3 (1←0)
Band origin 207.6 (199.3)
282.4 (294.0)
360.3 (368.7)
Jmax 50 50 80
Kmax 11 23 38
No of Lines 382 3719 5868
Fit RMS 0.00030 0.00015 0.00033
Accuracy 0.00047 0.000235 0.00047
Global fit: vibrational results (in cm-1)
Data in the 150-450 cm-1 range fitted at the experimental accuracy:
In parenthesis: ab initio values from M. L. Senent, JPCA 108 (2004) 6286
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
1212
The GA spectrum: perspectives
Analysis of the hotand combination bands
x3-3, x1-1 and x1-3 anharmonicity constants
Intramolecular H-bond properties(C-OH torsion not perturbed and high ~ 350 cm-1 / e.g. Ethanol ~ 200 cm-1)
The THz spectrum of GlycolAldehydeOSU ISMS – June 20-24 2011
Experimental and a- and b- type sticks spectrum of 2
3 (2←1)
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AcknowledgmentsFinancial funding: ANR « TopModel » (ANR-08-BLAN-0054);
Programme PCMI
and many thanks for your attention
T. HuetT. HuetT. Huet P. Roy
O. PiraliL. Margulès
I. Haykal
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Laboratoire de Physique des Lasers, Atomes et MoléculesTél. +33 (0)320 434785 | Fax. +33 (0) 320 337020 www-phlam.univ-lille1.fr
