Integral and differential cross sections of reactions relevant to astrochemistry

Costes, Michel; Naulin, Christian

doi:10.1039/c003656k

Cited by 15 publications

(8 citation statements)

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“…At the same time, the atomic carbon is much more reactive compared to carbon molecules. Fast low-temperature reactions between carbon atoms and many carbon bearing molecules have been previously reported (Chastaing et al 2001;Costes & Naulin 2010). Therefore, the low-temperature condensation of carbon atoms can give completely different results.…”

Section: Condensation Of Atomic Carbon Together With Common Ism Molec...mentioning

confidence: 99%

Low-temperature Condensation of Carbon

Krasnokutski

Goulart

Гордон

et al. 2017

ApJ

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Two different types of experiments were performed. In the first experiment we studied the low-temperature condensation of vaporized graphite inside bulk liquid helium while in the second experiment the condensation of single carbon atoms together with H2, H2O, and CO molecules inside helium nanodroplets was studied. The condensation of vaporized graphite leads to the formation of partially graphitized carbon, which indicates high-temperatures, supposedly higher than 1000 °C, during the condensation. Possible underlying processes responsible for the instant rise in temperature during condensation are discussed. This suggests that such processes cause the presence of partially graphitized carbon dust formed by low-temperatures condensation in the diffuse interstellar medium. Alternatively, in the denser regions of the ISM, the condensation of carbon atoms together with the most abundant interstellar molecules (H2, H2O, and CO), leads to the formation of complex organic molecules (COMs) and finally organic polymers.Water molecules were found not to be involved directly in the reaction network leading to the formation of COMs. It was proposed that COMs are formed via addition of carbon atoms to H2 and CO molecules (C + H2 → HCH, HCH + CO → OCCH2). Due to the involvement of molecular hydrogen, the formation of COMs by carbon addition reactions should be more efficient at high extinctions compared with the previously proposed reaction scheme with atomic hydrogen.

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Section: Condensation Of Atomic Carbon Together With Common Ism Molec...mentioning

confidence: 99%

Low-temperature Condensation of Carbon

Krasnokutski

Goulart

Гордон

et al. 2017

ApJ

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“…Luckily, emerging experimental techniques like the Crossed Stark decelerators [21] promise to provide detailed information on cold bimolecular collisions. More related with our work, CRESU (Reaction Kinetics in Uniform Supersonic Flow) experiments implemented in Rennes [22,23], and crossed molecular beam experiments performed in Bordeaux [24,25], are exploring barrierless reactions between neutral species in conditions aproaching the cold regime [26]. In particular, rate constants and cross-sections have been recently obtained for the title reaction at temperatures and kinetic energies as low as ∼ 5K (1K∼ 8.3 × 10 −3 KJ mol −1 ) [27].…”

Section: Introductionmentioning

confidence: 99%

Reaching the cold regime: S(1D) + H2 and the role of long-range interactions in open shell reactive collisions

Lara

Dayou

Launay

2011

Phys. Chem. Chem. Phys.

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Reactive cross-sections for the collision of open shell S( 1 D) atoms with ortho-and para-hydrogen, in the kinetic energy range 1−120 K, have been calculated using the hyperspherical quantum reactive scattering method developed by Launay et al. [Chem. Phys. Lett. 169, 473 (1990)]. Short-range interactions, described using the ab initio potential energy surface by Ho et al., were complemented with an accurate description of the longrange interactions, where the main electrostatic (∼ R −5 ) and dispersion (∼ R −6 ) contributions were considered. This allows the comparison with recent experimental measurements of rate constants and excitation functions for the title reaction at low temperatures [Berteloite et al., accepted in Phys. Rev. Lett., 2010]. The agreement is fairly good. The behavior in the considered energy range can be understood on the average in terms of a classical Langevin (capture) model, where the centrifugal barriers determine the amount of reactive flux which reaches the barrierless transition state. Additionally, the structure of the van der Waals well provides temporal trapping at short distances thus allowing the system to find its way to the reaction at some classically-forbidden energies. Interestingly, the cross-section for para-hydrogen shows clearly oscillating features associated to the opening of new partial waves and to shape resonances which may be amenable to experimental detection.

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“…[1][2][3][4][5][6][7] However, new experimental approaches are changing this scenario, providing detailed information on more generic bimolecular systems at very low collision energies, [8][9][10][11][12][13][14] eventually bridging the gap between cold (T < 1 K) and ultracold (T < 1 mK) regimes. [15][16][17][18][19] While the availability of new experimental results calls for computational studies to be extended to the ultracold regime, advances in the theoretical simulation of these processes are hampered by the limitation in the accuracy of the stateof-the-art electronic calculations, typically larger than the collision energies involved.…”

Section: Introductionmentioning

confidence: 99%

Cold and ultracold dynamics of the barrierless D+ + H2 reaction: Quantum reactive calculations for ∼R−4 long range interaction potentials

Lara

Jambrina

Aoiz

et al. 2015

The Journal of Chemical Physics

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Quantum reactive and elastic cross sections and rate coefficients have been calculated for D + + H 2 (v = 0, j = 0) collisions in the energy range from 10 −8 K (deep ultracold regime), where only one partial wave is open, to 150 K (Langevin regime) where many of them contribute. In systems involving ions, the ∼R −4 behavior extends the interaction up to extremely long distances, requiring a special treatment. To this purpose, we have used a modified version of the hyperspherical quantum reactive scattering method, which allows the propagations up to distances of 10 5 a 0 needed to converge the elastic cross sections. Interpolation procedures are also proposed which may reduce the cost of exact dynamical calculations at such low energies. (2000)], are also shown in order to emphasize the significance of the inclusion of the long range interactions. The calculated reaction rate coefficient changes less than one order of magnitude in a collision energy range of ten orders of magnitude, and it is found in very good agreement with the available experimental data in the region where they exist (10-100 K). State-to-state reaction probabilities are also provided which show that for each partial wave, the distribution of HD final states remains essentially constant below 1 K. C 2015 AIP Publishing LLC. [http://dx

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Integral and differential cross sections of reactions relevant to astrochemistry

Cited by 15 publications

References 100 publications

Low-temperature Condensation of Carbon

Low-temperature Condensation of Carbon

Reaching the cold regime: S(1D) + H2 and the role of long-range interactions in open shell reactive collisions

Cold and ultracold dynamics of the barrierless D+ + H2 reaction: Quantum reactive calculations for ∼R−4 long range interaction potentials

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