Transcript hn2cho_columbus11.pptx

The extended spectroscopic
database on formamide: parent,
13C and deuterated species up to
1 THz
A.S. Kutsenko
Institute of radio astronomy of NASU, Kharkov, Ukraine
R.A. Motiyenko, L. Margulès
PhLAM, Université Lille 1, France
J.-C. Guillemin
ENS de Chimie, Rennes, France
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Formamide
• The simplest interstellar molecule containing a
peptide bond: –C(=O)NH–
• Detected in Sgr B2 and Orion KL: Rubin et al
ApJ, 169 (1971) L39
• Spectroscopy (more than 10 publications):
Kryvda et al. J. Mol. Spec. 254 (2009) 28
• Normal species studied up to 490 GHz
•
13C, 15N
and 18O species studied up to 250 GHz
Deuterated species
•
Interest: H/D exchanges on grain surface
A. Ratajczak et al A&A 496 (2009), L21, A. Ratajczak et al A&A 528
(2011), L13:
• In case of solid H/D exchanges DCONH2 should be significantly more
abundant than HCONHD and HCONDH
• If alternative and/or additional processes play a role in the postevaporative gas-phase then the three deuterated isotopologues of
formamide could have a similar abundance
•
Spectroscopy
Kurland&Wilson J.Chem.Phys. 27(1957); Costain&Dowling J.Chem.Phys.
32(1960)
• Measurements up to 43 GHz
• A,B,C rotational constants + hyperfine structure
New measurements in Lille
1. HCONH2 sample (solid state sources: 400 – 465 GHz and 800 – 935
GHz, BWO: 580 – 660 GHz)
• parent species v=0 and v12=1
• 13C species in natural abundance
2. Deuterated samples (solid states sources 150 – 950 GHz)
• DCOHN2
• a « soup » of HCONHD, HCONDH and HCOND2
Lille BWO-based spectrometer
HV Power
Supply
RS-232
PLL,
IF=8.7 – 11.8
MHz
BWO
580 – 660
GHz
Absorbing cell
F/32
+
IF Amplifier
Synthesizer
Agilent E8257D
12.5 – 16.5 GHz
DDS
8.7 – 11.8 MHz
Internal bus
RS-232
RS-232
Bolometer
Amplifier
SR7270
DSP Lock-in
amplifier
Normal species spectra
580 – 660 GHz
800 – 935 GHz
421,42 – 411,41
420,42 – 410,41
NH213CHO
Deuterated species spectra
Denser spectrum due to « soup » mixture
parent/cis/trans/D2
44 : 22 : 22 : 12
Results: spectroscopy
• frequency range of measurements is extended up to 945 GHz
• accurate prediction of transition frequencies up to 1.5 THz
N data
Our
contribution
Jmax, Ka/max
rms (MHz)
wrms
HCONH2
1630
709
65, 24
0.028
0.72
HCONH2, v12
1243
581
63, 22
0.029
0.70
H13CONH2
409
190
45, 15
0.029
0.70
DCONH2
1278
1271
58, 28
0.026
0.69
c-HCONHD
646
638
52, 20
0.021
0.64
t-HCONHD
588
581
54, 20
0.022
0.60
HCOND2
437
431
38, 20
0.023
0.73
Results: detection of v12 state (289 cm-1)
in Orion KL
in collaboration with B. Tercero and J. Cernicharo
Acknowledgements
• French embassy in Ukraine
• Programme National de Physico-Chimie du Milieu Interstellaire - CNRS
• ANR-08-BLAN-0054
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