J/ApJ/748/99 Reactions of acetic acid with hydroxylamine (Barrientos+, 2012)
Gas-phase synthesis of precursors of interstellar glycine: a computational study
of the reactions of acetic acid with hydroxylamine and its ionized and
protonated derivatives.
Barrientos C., Redondo P., Largo L., Rayon V.M., Largo A.
<Astrophys. J., 748, 99 (2012)>
=2012ApJ...748...99B 2012ApJ...748...99B
ADC_Keywords: Atomic physics ; Interstellar medium
Keywords: astrobiology - astrochemistry - ISM: molecules - molecular processes
Abstract:
A computational study of the reactions of hydroxylamine and its
ionized and protonated derivatives with acetic acid is provided. The
reaction of neutral hydroxylamine with acetic acid, despite being
clearly exothermic, involves a very large energy barrier. The reaction
of ionized hydroxylamine with acetic acid is also clearly exothermic,
but again a significant energy barrier is found (around 24 kcal/mol at
the CCSD(T) level). The reaction of the most stable protonated isomer
of hydroxylamine, NH3OH+, with acetic acid also involves a high
barrier (more than 27 kcal/mol at the CCSD(T) level). Only the higher
energy isomer, NH2OH+2, leads to a sensibly lower energy barrier
(about 2.3 kcal/mol at the CCSD(T) level). Nevertheless, an estimate
of the reaction coefficient at low temperatures such as those reigning
in the interstellar medium gives very low values. Therefore, it seems
that precursors of interstellar glycine could not be efficiently
produced from the reactions of hydroxylamine-derived ions with acetic
acid.
Description:
The geometries of the different species reported in this work have
been obtained at the second-order Moller-Plesset level. In these
optimizations the cc-pVTZ (correlation-consistent polarized valence
triple-zeta) basis set developed by Dunning (1989JChPh..90.1007D 1989JChPh..90.1007D;
Kendall et al. 1992JChPh..96.6796K 1992JChPh..96.6796K) has been employed. The different
optimized structures were verified to be a stationary point or a
transition state (TS) by vibrational analysis carried out at the same
level (MP2/cc-pVTZ).
In order to compute more accurate relative energies CCSD(T)
calculations (coupled-cluster single and double excitation model
augmented with a non-iterative triple excitation correction;
Raghavachari et al. 1989CPL...157..479R 1989CPL...157..479R) have been carried out on the
MP2/cc-pVTZ geometries. The aug-cc-pVTZ basis set, which also includes
diffuse functions, has been employed for the energetic calculations.
Zero-point vibrational energy corrections were included at the
MP2/cc-pVTZ level.
All calculations reported in this work were carried out with the
Gaussian-09 program package (Frisch, M. J., Trucks, G. W., & Schlegel,
H. B. et al. 2009, Gaussian 09 (Wallingford, CT: Gaussian Inc.)).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 50 290 Cartesian coordinates for the intermediates and
transition states of the reaction of hydroxylamine
(NH2OH) species with acetic acid.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Species Transition state (1)
8 A1 --- Atom [HCNO] Element of the hydroxylamine molecule
10- 22 F13.10 0.1nm X X cartesian coordinate
24- 36 F13.10 0.1nm Y Y cartesian coordinate
38- 50 F13.10 0.1nm Z Z cartesian coordinate
--------------------------------------------------------------------------------
Note (1): In the case of neutral reaction, PRC1 and PRC2 designate the
intermediate states, TS1 and TS2 the transition states. For the
ionized reactions, the states are designated with an additional +
(e.g. PRC1+), and the protonated with an additional H+ (e.g. PRC1H+).
See Fig.2
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Oct-2013