H2(v= 0,1) + C+(2P) → H+CH+STATE-TO-STATE RATE CONSTANTS FOR CHEMICAL PUMPING MODELS IN ASTROPHYSICAL MEDIA

Zanchet, Alexandre; Godard, B.; Bulut, Niyazi; Roncero, Octavio; Halvick, Philippe; Cernicharo, J.

doi:10.1088/0004-637x/766/2/80

Cited by 80 publications

(116 citation statements)

References 68 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…The situation in the system under study is clearly immediate, favoring the formation of H 2 in v = 1 and 2. This provides another possibility for the formation of vibrationally excited H 2 , which is of interest in the chemistry of the interstellar medium because it allows the occurrence of endothermic reactions (Agundez et al 2010;Godard & Cernicharo 2013), as recently shown for the C + + H 2 system (Zanchet et al 2013). The initial rotational states of LiH (v = 0) considered are just j = 0 and 1, and its contribution to the total angular momentum can be neglected, such that J can be considered proportional to the classical impact parameter.…”

mentioning

confidence: 81%

STATE-TO-STATE QUANTUM WAVE PACKET DYNAMICS OF THE LiH + H REACTION ON TWO AB INITIO POTENTIAL ENERGY SURFACES

Gómez-Carrasco

González-Sánchez

Bulut

et al. 2014

ApJ

View full text Add to dashboard Cite

The dynamics and kinetics of the LiH + H reaction have been studied by using an accurate quantum reactive time-dependent wave packet method on the ab initio ground electronic state potential energy surfaces (PES) developed earlier. Reaction probabilities for the two possible reaction channels, the LiH + H→ H 2 + Li depletion process and the LiH + H→H + LiH hydrogen exchange reaction, have been calculated from 1 meV up to 1.0 eV collision energies for total angular momenta J from 0 to 80. State-to-state and total integral cross sections for the LiH-depletion and H-exchange channels of the reaction have been calculated over this collision energy range. It is found that the LiH-depletion channel is dominant in the whole range of collision energies for both PESs. Accurate total rate coefficients have been calculated on both surfaces from 100 K to 2000 K and are significantly larger than previous empirical estimates and previous J-shifting results. In addition, the present accurate calculations present noticeable differences with previous calculations using the centrifugal sudden approximation.

show abstract

mentioning

confidence: 81%

STATE-TO-STATE QUANTUM WAVE PACKET DYNAMICS OF THE LiH + H REACTION ON TWO AB INITIO POTENTIAL ENERGY SURFACES

Gómez-Carrasco

González-Sánchez

Bulut

et al. 2014

ApJ

View full text Add to dashboard Cite

show abstract

“…Laboratory experiments (Hierl, Morris & Viggiano 1997) and quantum calculations (e.g. Zanchet et al 2013b), however, show that the reaction becomes exothermic when H * 2 , and not H 2 (v=0), is the reactant. The reaction rate k * then reaches the Langevin limiting case, and becomes almost independent of the temperature.…”

Section: The Role Of Vibrationally Excited H 2 In the Chemistrymentioning

confidence: 99%

Interstellar Hydrides

Gérin

Neufeld

Goicoechea

2016

Annu. Rev. Astron. Astrophys.

129

171

View full text Add to dashboard Cite

Interstellar hydrides -that is, molecules containing a single heavy element atom with one or more hydrogen atoms -were among the first molecules detected outside the solar system. They lie at the root of interstellar chemistry, being among the first species to form in initially-atomic gas, along with molecular hydrogen and its associated ions. Because the chemical pathways leading to the formation of interstellar hydrides are relatively simple, the analysis of the observed abundances is relatively straightforward and provides key information about the environments where hydrides are found. Recent years have seen rapid progress in our understanding of interstellar hydrides, thanks largely to far-IR and submillimeter observations performed with the Herschel Space Observatory. In this review, we will discuss observations of interstellar hydrides, along with the advanced modeling approaches that have been used to interpret them, and the unique information that has thereby been obtained.

show abstract

“…Fig.10 of Hierl et al (1997) suggest a possible weak temperature dependence. Zanchet et al (2013b) performed quantum calculations to derive state-to-state reaction rates for the system C + and H 2 . In the following, we neglect the formation excitation of CH + and use the parametrized rate from Zanchet et al (2013a) for H 2 (v = 1) ( Table 3) The theoretical calculations are a factor 4 lower than the laboratory work from Hierl et al (1997) (Fig.…”

Section: Appendix A: Chemical Reaction Ratesmentioning

confidence: 99%

Consistent dust and gas models for protoplanetary disks

Kamp

Thi

Woitke

et al. 2017

A&A

109

View full text Add to dashboard Cite

Aims. We define a small and large chemical network which can be used for the quantitative simultaneous analysis of molecular emission from the near-IR to the submm. We revise reactions of excited molecular hydrogen, which are not included in UMIST, to provide a homogeneous database for future applications. Methods. We use the thermo-chemical disk modeling code ProDiMo and a standard T Tauri disk model to evaluate the impact of various chemical networks, reaction rate databases and sets of adsorption energies on a large sample of chemical species and emerging line fluxes from the near-IR to the submm wavelength range. Results. We find large differences in the masses and radial distribution of ice reservoirs when considering freeze-out on bare or polar ice coated grains. Most strongly the ammonia ice mass and the location of the snow line (water) change. As a consequence molecules associated to the ice lines such as N 2 H + change their emitting region; none of the line fluxes in the sample considered here changes by more than 25% except CO isotopologues, CN and N 2 H + lines. The three-body reaction N+H 2 +M plays a key role in the formation of water in the outer disk. Besides that, differences between the UMIST 2006 and 2012 database change line fluxes in the sample considered here by less than a factor 2 (a subset of low excitation CO and fine structure lines stays even within 25%); exceptions are OH, CN, HCN, HCO + and N 2 H + lines. However, different networks such as OSU and KIDA 2011 lead to pronounced differences in the chemistry inside 100 au and thus affect emission lines from high excitation CO, OH and CN lines. H 2 is easily excited at the disk surface and state-to-state reactions enhance the abundance of CH + and to a lesser extent HCO + . For sub-mm lines of HCN, N 2 H + and HCO + , a more complex larger network is recommended. Conclusions. More work is required to consolidate data on key reactions leading to the formation of water, molecular ions such as HCO + and N 2 H + as well as the nitrogen chemistry. This affects many of the key lines used in the interpretation of disk observations. Differential analysis of various disk models using the same chemical input data will be more robust than the interpretation of absolute fluxes.

show abstract

H₂(v= 0,1) + C⁺(²P) → H+CH⁺STATE-TO-STATE RATE CONSTANTS FOR CHEMICAL PUMPING MODELS IN ASTROPHYSICAL MEDIA

Cited by 80 publications

References 68 publications

STATE-TO-STATE QUANTUM WAVE PACKET DYNAMICS OF THE LiH + H REACTION ON TWO AB INITIO POTENTIAL ENERGY SURFACES

STATE-TO-STATE QUANTUM WAVE PACKET DYNAMICS OF THE LiH + H REACTION ON TWO AB INITIO POTENTIAL ENERGY SURFACES

Interstellar Hydrides

Consistent dust and gas models for protoplanetary disks

Contact Info

Product

Resources

About