Renner-Teller effects in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mi>HCO</mml:mi><mml:mo>+</mml:mo></mml:msup></mml:mrow></mml:math>dissociative recombination

Михайлов, И. В.; Kokoouline, Viatcheslav; Larson, Åsa; Tonzani, Stefano; Greene, Chris H.

doi:10.1103/physreva.74.032707

Cited by 38 publications

(95 citation statements)

References 38 publications

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“…In this present study, we have calculated the cross section for HCO + (solid magenta line) as well as a cross section assuming 10% of contribution from the HOC + isomer (orange dashed line). For both cases, there is an overall improvement in agreement with the experiment comparing to our previous models [5,27] as well as to the results of Jungen and Pratt [12], especially if we compare our results with the flowing afterglow experiment by Le Padellec et al [36]. Both experimental cross sections present a drop at about 840 cm −1 , which corresponds to the vibrational threshold of the doubly degenerate transverse mode of HOC + .…”

Section: Resultssupporting

confidence: 75%

“…This coupling was neglected in previous studies [5,27], which explains partially the difference between cross sections obtained in Refs. [5,27] and in this study, which is demonstrated in Fig. 5.…”

Section: Theoretical Approachmentioning

confidence: 90%

“…It is also present in the Martian atmosphere [26]. The indirect DR mechanism of this ion has actually been studied extensively [4,5,12,27,28], however the calculations still remain a factor 2-3 lower than the experimental values. On the view of the successful results obtained in the highly symmetric molecular ions H 3 O + [14], CH + 3 [15] and NH + 4 [16], we have included the HCO + in the present study in an attempt to produce a better theoretical DR cross-section for this molecular ion at low energies.…”

Section: Introductionmentioning

confidence: 98%

“…The electron can be temporarily captured into a rovibrationally excited Rydberg state of the neutral molecule which, if the auto-ionization lifetime is sufficiently long, would find a pathway to dissociate through a cascade of lower Rydberg states coupled to each other through non-adiabatic effects. The indirect mechanism has been shown to be efficient in numerous systems, such as H + 3 [1], HeH + [2,3], and HCO + [4,5]. On the other hand, recent theoretical work has demonstrated that the direct DR mechanism is not an EPJ Web of Conferences efficient mechanism at low energy in HCNH + [6] and N 2 H + [7].…”

Section: Introductionmentioning

confidence: 99%

“…Following Refs. [5,30], the description of the vibrational dynamics in the simplified model developed by Jungen and Pratt [12,13] considers the electronic capture as the decisive step in the DR mechanism neglecting auto-ionization; i.e., after the neutral molecule is formed all the flux is transferred into dissociation. Therefore, within this approximation, the DR cross section is an upper bound since it does not reflect the competition between dissociation and auto-ionization.…”

Section: Theoretical Approachmentioning

confidence: 99%

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Simplified model to describe the dissociative recombination of linear polyatomic ions of astrophysical interest

Douguet

Santos

Kokoouline

et al. 2015

EPJ Web of Conferences

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Abstract. We present results of a theoretical study on dissociative recombination of the HCNH + , HCO + and N 2 H + linear polyatomic ions at low energies using a simple theoretical model. In the present study, the indirect mechanism for recombination proceeds through the capture of the incoming electron in excited vibrational Rydberg states attached to the degenerate transverse modes of the linear ions. The strength of the non-adiabatic coupling responsible for dissociative recombination is determined directly from the near-threshold scattering matrix obtained numerically using the complex Kohn variational method. The final cross sections for the process are compared with available experimental data. It is demonstrated that at low collision energies, the major contribution to the dissociative recombination cross section is due to the indirect mechanism.

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Section: Resultssupporting

confidence: 75%

Section: Theoretical Approachmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Theoretical Approachmentioning

confidence: 99%

See 3 more Smart Citations

Simplified model to describe the dissociative recombination of linear polyatomic ions of astrophysical interest

Douguet

Santos

Kokoouline

et al. 2015

EPJ Web of Conferences

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Reaction Networks for Interstellar Chemical Modelling: Improvements and Challenges

Smith²,

et al. 2010

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We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes-ion-neutral reactions, neutral-neutral reactions, radiative association, and dissociative recombination-is reviewed. Emphasis is placed on those key reactions that have been identified, by sensitivity analyses, as 'crucial' in determining the predicted abundances of the species observed in the interstellar medium. These sensitivity analyses have been carried out for gas-phase models of three representative, molecule-rich, astronomical sources: the cold dense molecular clouds TMC-1 and L134N, and the expanding circumstellar envelope IRC +10216. Our review has led to the proposal of new values and uncertainties for the rate coefficients of many of the key reactions. The impact of these new data on the predicted abundances in TMC-1 and L134N is reported. Interstellar dust particles also influence the observed abundances of molecules in the interstellar medium. Their role is included in gas-grain, as distinct from gas-phase only, models. We review the methods for incorporating both accretion onto, and reactions on, the surfaces of grains in such models, as well as describing some recent experimental efforts to simulate and examine relevant processes in the laboratory. These efforts include experiments on the surface-catalyzed recombination of hydrogen atoms, on chemical processing on and in the ices that are known to exist on the surface of interstellar grains, and on desorption processes, which may enable species formed on grains to return to the gas-phase.

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