J/A+A/616/A150 HNCO in planetary atmospheres. (Ferus+, 2018)
HNCO-based synthesis of formamide in planetary atmospheres.
Ferus M., Laitl V., Knizek A., Kubelik P., Sponer J., Kara J., Sponer J.E.,
Lefloch B., Cassone G., Civis S.
<Astron. Astrophys. 616, A150 (2018)>
=2018A&A...616A.150F 2018A&A...616A.150F (SIMBAD/NED BibCode)
ADC_Keywords: Models, atmosphere ; Spectra, ultraviolet ; Spectra, optical ;
Spectra, infrared
Keywords: astrochemistry - astrobiology - planets and satellites: atmospheres -
ISM: molecules
Abstract:
Time-resolved Fourier transform infrared emission spectroscopy,
Fourier transform absorption infrared spectroscopy, and
high-resolution UV-ViS emission spectroscopy have been exploited in
order to characterize the chemistry of isocyanic acid (HNCO) under
glow discharge conditions in planetary atmospheres. HNCO mixtures
(i.e., composed of di-hydrogen or ammonia) have been investigated in
order to unveil the possible reaction pathways leading to the
synthesis of the key prebiotic molecule formamide (HCONH2), upon
planetary atmospheres containing isocyanic acid in presence of
di-hydrogen and, separately, of ammonia. In addition, ab initio
Molecular Dynamics simulations coupled with a state-of-the-art
metadynamics technique have been performed in order to identify the
most likely chemical pathways connecting HNCO to formamide. It turned
out that the direct hydrogenation of HNCO is thermodynamically
favored. Incidentally, also the experimental results - supplied by a
simplified kinetic model - proved the favorability of the reaction
HNCO + H2 -> HCONH2 which, moreover, spontaneously takes place in
unbiased ab initio Molecular Dynamics simulations carried out under
the effect of intense electric fields.
Description:
Several spectroscopic measurements have been performed to identify the
chemistry underlying HNCO, HNCO + H2, and HNCO + NH3 mixtures
under glow discharge conditions. High-resolution Fourier transform
infrared absorption spectroscopy has been employed in order to monitor
the stable gas phase products, particularly formamide as a product of
reverse reactions of HNCO decomposition. Emission spectra are examined
by UV-ViS and time resolved FTIR spectroscopy. The results have been
compared with ab initio molecular dynamics and metadynamics
simulations in order to propose an adequate reaction scheme.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig2a.dat 23 232310 Absorption spectra of the discharge products
formed in HNCO + He
fig2b.dat 23 358566 Absorption spectra of the discharge products
formed in HNCO + H2
fig2bd.dat 23 14836 Formamide carbonyl v4 band observed in 10 ppm
of vapors formamide vapors
fig2c.dat 23 358419 Absorption spectra of the discharge products
formed in HNCO + NH3
fig3.dat 15 54396 UV-Vis emission spectra of the glow discharge
in mixture of HNCO with hydrogen
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See also:
J/A+A/361/1079 : HNCO in massive galactic dense cores (Zinchenko, 2000)
J/PAZh/33/143 : Laboratory studies of HNCO (Lapinov+, 2007)
Byte-by-byte Description of file: fig2a.dat fig2b.dat fig2bd.dat fig2c.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 nm lambda Wavelength
16- 23 F8.5 --- Trans Transmittance (1)
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Note (1): ratio between the intensity of the light travelling through the
measured gas and from the source without the gas.
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Byte-by-byte Description of file: fig3.dat
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Bytes Format Units Label Explanations
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1- 7 F7.3 nm lambda Wavelength
9- 15 F7.4 --- Int Emission intensity in arbitrary units
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Acknowledgements:
Giuseppe Cassone, cassone(at)ibp.cz
(End) Patricia Vannier [CDS] 06-Jun-2018