1. THE MILLIMETER-WAVE SPECTRUM OF VINYL ACETATE
Grupo de Espectroscopía Molecular, Lab. de Espectroscopia y Bioespectroscopia
Edificio Quifima, Unidad Asociada CSIC, Universidad de Valladolid, Valladolid, Spain
Departamento de Astrofísica, Centro de Astrobiología, CAB, CSIC-INTA, Madrid, Spain
CNRS et Universités Paris Est et Paris Diderot, Laboratoire Interuniversitaire
des Systèmes Atmosphériques (LISA), Creteil, France
THE MILLIMETER-WAVE SPECTRUM OF
VINYL ACETATE
Lucie Kolesniková, Isabel Peña, José L. Alonso, José Cernicharo, Belén Tercero, Isabelle Kleiner
International Symposium on Molecular Spectroscopy, June 16  20, 2014
Champaign-Urbana, Illinois, USA

2. Introduction and motivation
Methyl acetate (CH3COOCH3)
Gauche-ethyl formate (g-CH3CH2OCOH)
detected in ORION KLa
detected in Sgr B2b
a Tercero B. , Kleiner I., Cernicharo J. , Nguyen H. V. L., Lopez A. , and Muñoz Caro G. M., 2013, ApJ. 770, L13.
b Belloche, A., Garrod, R. T., Műller, H. S. P., et al. 2009, A&A, 499, 215.

3. Introduction and motivation
Methyl acetate (CH3COOCH3)
Gauche-ethyl formate (g-CH3CH2OCOH)
Methyl acetate (CH3COOCH3)
Gauche-ethyl formate (g-CH3CH2OCOH)
Vinyl acetate (CH3COOCHCH2) – one of the simplest unsaturated carboxylic ester
Previous data up to 77 GHzc → new data → search in Orion KL
detected in ORION KLa
detected in Sgr B2b
acetate containing molecules are potential candidates
a Tercero B. , Kleiner I., Cernicharo J. , Nguyen H. V. L., Lopez A. , and Muñoz Caro G. M., 2013, ApJ. 770, L13.
b Belloche, A., Garrod, R. T., Műller, H. S. P., et al. 2009, A&A, 499, 215.
c Velino B., Maris A., Melandri S., Caminati W. J Mol. Spectrosc. 256 (2009) 228 – 231.

4. Vinyl acetate molecule
Predicted conformersb
DE = 0 cm1
DE = 1060 cm1
DE = 2313 cm1
b Velino B., Maris A., Melandri S., Caminati W. J Mol. Spectrosc. 256 (2009) 228 – 231.

5. Vinyl acetate molecule
MP2/ g(d,p):
ma = 0.04 D
mb = D
mc = 0.09 D
The most stable conformer
Previous data (61 – 77 GHz)b  predictions (BELGI-Cs)
Velino et. al.b:
V3 = (93) cm1
A-E splitting
b Velino B., Maris A., Melandri S., Caminati W. J Mol. Spectrosc. 256 (2009) 228 – 231.

6. CP-FTMW spectra: experiment
CP-FTMW spectrometer (6 – 18 GHz)c
Supersonic Expansion
2 nozzels
Ne carrier gas (2 bar)
Broadband FT-MW spectrometer
c S. Mata I. Peña, C. Cabezas, J. C. López and J. L. Alonso. J. Mol. Spectrosc. 280 (2012) 91–96

7. CP-FTMW spectra: analysis
6 – 18 GHz

8. CP-FTMW spectra: analysis
6 – 18 GHz
2 1 1  2 0 2
1 1 1  0 0 0
2 1 2  1 0 1
1 1 0  1 0 1 A E E A E A A E
3 1 2  3 0 3 A E

9. CP-FTMW spectra: analysis
6 – 18 GHz
2 1 1  2 0 2
1 1 1  0 0 0
2 1 2  1 0 1
1 1 0  1 0 1 A E E A E A A E
3 1 2  3 0 3 A E

10. CP-FTMW spectra: analysis
6 – 18 GHz
2 1 1  2 0 2
1 1 1  0 0 0
2 1 2  1 0 1
1 1 0  1 0 1 A E E A E A A E
3 1 2  3 0 3 A E
Parent species
A-lines:  1 0 1
13C3
13C2
13C1
13C4
18O1
18O2

11. CP-FTMW spectra: analysis
6 – 18 GHz
2 1 1  2 0 2
1 1 1  0 0 0
2 1 2  1 0 1
1 1 0  1 0 1 A E E A E A A E
3 1 2  3 0 3 A E
assignments of the transitions of the parent species and isotopologues
search for the second conformer
Parent species
A-lines:  1 0 1
13C3
13C2
13C1
13C4
18O1
18O2

12. CP-FTMW spectra: results
A-species rotational constants (MHz)
Parent species
13C1
13C2
13C3
13C4
18O1
18O2 A
(86)
(92)
(98)
(12)
(58)
(11)
(23) B
(16)
(46)
(21)
(17)
(27)
(91)
(24) C
(17)
(27)
(29)
(69)
(16)
(48)
(12)
Atom
Substitution coordinates (Å)
(assumption of the symmetry plane)
|a|
|b| C1
(58)
(57) C2
(11)
(51) C3
(17)
0.080 (19) C4
(74)
(16) O1
(57)
(29) O2
(14)
(12)

13. MMW spectra: experiment
MMW and sub-MMW spectrometer (50 – 1000 GHz)
129 – 360 GHz
room temperature
20 mbar

14. MMW spectra: experiment
MMW and sub-MMW spectrometer (50 – 1000 GHz)
129 – 360 GHz
room temperature
20 mbar
Synthesizer
Sample cells
Lock-in amplifier
AM chains
Lens

15. MMW spectra: experiment
MMW and sub-MMW spectrometer (50 – 1000 GHz)
Roof-top mirror
Detector
Synthesizer
Sample cells
Lock-in amplifier
AM chains
Lens

16. MMW spectra: analysis
MMW spectrum E A E A E A E A
E A A

17. MMW spectra: analysis
AABS package:
ncent (MHz)
Dn (MHz)

18. MMW spectra: analysis E A E A E A E A Ka’’ = 3, 4 Ka’’ = 2, 3
ncent (MHz) E A E A E A E A
Dn (MHz)

19. MMW spectra: analysis J’’ = 95, Ka’’ = 16 J’’ = 95, Ka’’ = 10
ncent (MHz) E A E A E A E A
CP-FTMW + MMW spectra
> transitions (A-species)
J’’ = 95, Ka’’ = 16
> 900 transitions (E-species)
J’’ = 95, Ka’’ = 10
BELGI-Cs code (rho-axis method)
Dn (MHz)

20. CP-FTMW + MMW spectra: results
Operatora
Constant
Unit
Value
Pa2 A
cm-1
(31)
Pb2 B
(11)
Pc2 C
(45)
{Pa,Pb}
Dab
(45)
{Pa,Pc}(sin3)
Dac
(13)
-P4
DJ x 10-8
(48)
-Pa4
DK x 10-6
(46)
-2P2(Pb2-Pc2)
J x 10-9
(24)
-2Pa2(Pb2-Pc2)
K x 10-8
0.957 (17)
P2 F
[ ]
(1/2)(1-cos3) V3
(44)
PaP 
unitless
(35)
P 2 (Pa Pb + Pb Pa)
Dab x 10-5
0.638 (35)
(1-cos3)Pa2
k5 x 10-2
(94)
(1-cos3)P2
FV x 10-3
(75)
(1-cos3)(Pb2-Pc2)
c2 x 10-4
(79)
(1-cos3){Pa,Pb}
dAB
(60)
PgPa P2 Lv
(44)
P4Pa2
HJK x 10-13
0.270 (40)
Current fit:
J’’ = 75
18 floated torsion-rotation parameters
F constant fixed to the value obtained by XIAM
(Velino B., Maris A., Melandri S., Caminati W.
J Mol. Spectrosc. 256 (2009) 228 – 231.)
a In the rho-axis system

21. CP-FTMW + MMW spectra: results
Operatora
Constant
Unit
Value
Pa2 A
cm-1
(31)
Pb2 B
(11)
Pc2 C
(45)
{Pa,Pb}
Dab
(45)
{Pa,Pc}(sin3)
Dac
(13)
-P4
DJ x 10-8
(48)
-Pa4
DK x 10-6
(46)
-2P2(Pb2-Pc2)
J x 10-9
(24)
-2Pa2(Pb2-Pc2)
K x 10-8
0.957 (17)
P2 F
[ ]
(1/2)(1-cos3) V3
(44)
PaP 
unitless
(35)
P 2 (Pa Pb + Pb Pa)
Dab x 10-5
0.638 (35)
(1-cos3)Pa2
k5 x 10-2
(94)
(1-cos3)P2
FV x 10-3
(75)
(1-cos3)(Pb2-Pc2)
c2 x 10-4
(79)
(1-cos3){Pa,Pb}
dAB
(60)
PgPa P2 Lv
(44)
P4Pa2
HJK x 10-13
0.270 (40)
New laboratory data up to 360 GHz
principal axis-system
New set of the spectroscopic constants
Current fit:
J’’ = 75
18 floated torsion-rotation parameters
F constant fixed to the value obtained by XIAM
Search for the vinyl acetate in Orion KL
(Velino B., Maris A., Melandri S., Caminati W.
J Mol. Spectrosc. 256 (2009) 228 – 231.)
a In the rho-axis system

22. Molecular Astrophysics
Acknowledgements
Grants CTQ ,
AYA and AYA
Grant VA070A08
CSD
Molecular Astrophysics
…and all the members of the