On the dynamics of the H++D2(v=,j=)→HD+D+ reaction: A comparison between theory and experiment

Carmona‐Novillo, Estela; González‐Lezana, Tomás; Roncero, Octavio; Honvault, Pascal; Launay, Jean–Michel; Bulut, Niyazi; Aoiz, F. J.; Bañares, Luis; Trottier, Alexandre; Wrede, Eckart

doi:10.1063/1.2812555

Cited by 63 publications

(115 citation statements)

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“…Motivated for this experimental work, comparisons with theoretical results obtained in exact quantum mechanical ͑EQM͒ ͑that is, fully converged close coupling͒ and quasiclassical trajectory ͑QCT͒ calculations were soon reported. 3,[5][6][7] QCT angular distributions were found to be more symmetric about the sideway scattering direction ͑ ϳ 90°͒ than the corresponding experimental result at a collision energy of E c = 0.524 eV. 3 Hayes and Skodje 6 showed that at least part of the apparent slight asymmetry of the measured DCS could be attributed to an attenuation of the TOF signal as a function of the scattering angle due to the finite lifetime of the Rydberg state.…”

Section: Introductionmentioning

confidence: 97%

“…Recent experimental studies by means of the Rydberg H-atom translational spectroscopy technique 1 have enabled the analysis of translational energy distributions, time-of-flight ͑TOF͒ spectra, differential cross sections ͑DCSs͒, and relative rotational populations for the H ‫ء‬ ͑n͒ +D 2 reaction, [2][3][4][5] where H ‫ء‬ ͑n͒ corresponds to a highly excited Rydberg H atom. Due to this high excitation, H͑n ϳ 35͒, the Rydberg excited H atom behaves in practice as an ion, H + , during the collision with D 2 .…”

Section: Introductionmentioning

confidence: 99%

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Effects of the rotational excitation of D2 and of the potential energy surface on the H++D2→HD+D+ reaction

González‐Lezana

Honvault

Jambrina

et al. 2009

The Journal of Chemical Physics

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The H + +D 2 → HD+ D + reaction has been theoretically investigated by means of an exact quantum mechanical approach, a quasiclassical trajectory method, and two statistical methods based in the propagation of either wave functions or trajectories. The study addresses the possible changes on the overall dynamics of the title reaction when the D 2 diatom is rotationally excited to its v =0, j =1 state. In addition, the reactivity for the ground rotational state on two different potential energy surfaces ͑PESs͒, namely, the surface by Aguado et al. ͓J. Chem. Phys. 112, 1240 ͑2000͔͒ and the PES by Kamisaka et al. ͓J. Chem. Phys. 116, 654 ͑2002͔͒, is examined. Reaction probabilities and cross sections at 0.524 and 0.1 eV collision energies are calculated. The major differences with respect to the reaction initiated with D 2 in its ground rovibrational state are observed for the lowest collision energy E c = 0.1 eV. Differential cross sections have been found to depend to some extend on the PES employed. In addition, at E c = 0.1 eV further discrepancies in the total and rotational cross sections are noticeable.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Effects of the rotational excitation of D2 and of the potential energy surface on the H++D2→HD+D+ reaction

González‐Lezana

Honvault

Jambrina

et al. 2009

The Journal of Chemical Physics

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“…The application of different statistical techniques has provided good estimates of both quantum mechanical (QM) calculations and experimental work performed on the system. Thus, for instance, most of the information inferred from Rydberg H-atom time-offlight spectroscopic measurements [27][28][29] have been successfully reproduced 30,31 by means of a statistical quantum mechanical (SQM) method. 32,33 Different alternative approaches based on the assumption of the formation of an intermediate complex with a long enough lifetime before its fragmentation proved adequate to describe the dynamics of the process.…”

Section: Introductionmentioning

confidence: 99%

“…These two approaches have been applied in common for a better understanding of the dynamics of several atomdiatom reactions such as N+H 2 , 53 O+OH, 54 H + +H 2 , 4,55,56 and H + +D 2 . 14,31 Numerical details of the TIQM calculation performed by Honvault and Scribano were given before. 49 The number of rovibrational states for the reactant and product channels and of helicity components was found to guarantee converged results down to energies within the 10 −4 eV-10 −3 eV range.…”

Section: Theorymentioning

confidence: 99%

Dynamics of the D+ + H2 → HD + H+ reaction at the low energy regime by means of a statistical quantum method

González‐Lezana

Honvault

Scribano

2013

The Journal of Chemical Physics

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The D + +H 2 (v = 0, j = 0, 1) → HD+H + reaction has been investigated at the low energy regime by means of a statistical quantum mechanical (SQM) method. Reaction probabilities and integral cross sections (ICSs) between a collisional energy of 10 −4 eV and 0.1 eV have been calculated and compared with previously reported results of a time independent quantum mechanical (TIQM) approach. The TIQM results exhibit a dense profile with numerous narrow resonances down to E c ∼ 10 −2 eV and for the case of H 2 (v = 0, j = 0) a prominent peak is found at ∼2.5 × 10 −4 eV. The analysis at the state-to-state level reveals that this feature is originated in those processes which yield the formation of rotationally excited HD(v = 0, j > 0). The statistical predictions reproduce reasonably well the overall behaviour of the TIQM ICSs at the larger energy range (E c ≥ 10 −3 eV). Thermal rate constants are in qualitative agreement for the whole range of temperatures investigated in this work, 10-100 K, although the SQM values remain above the TIQM results for both initial H 2 rotational states, j = 0 and 1. The enlargement of the asymptotic region for the statistical approach is crucial for a proper description at low energies. In particular, we find that the SQM method leads to rate coefficients in terms of the energy in perfect agreement with previously reported measurements if the maximum distance at which the calculation is performed increases noticeably with respect to the value employed to reproduce the TIQM results. © 2013 AIP Publishing LLC.

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“…At energies below ≈1.7 eV, the proton exchange is the only reactive channel, and the process can be described on the ground adiabatic PES [19][20][21][22]. Since the PES is characterized by a deep well or complex (≈4.5 eV), as illustrated in Fig.…”

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confidence: 99%

Beyond universality: Parametrizing ultracold complex-mediated reactions using statistical assumptions

et al. 2015

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We have calculated accurate quantum reactive and elastic cross sections for the prototypical barrierless reaction D + + H 2 (v = 0, j = 0) using a modified hyperspherical scattering method. The considered kinetic energy ranges from the ultracold to the Langevin regimes. A reaction rate coefficient practically constant in no less than eight orders of magnitude is obtained. The availability of accurate results for this system allows one to test the quantum theory by Jachymski et al. [K. Jachymski, M. Krych, P. S. Julienne, and Z. Idziaszek, Phys. Rev. Lett. 110, 213202 (2013)] in a nonuniversal case. The short-range reaction probability is rationalized using statistical model assumptions and related to a statistical factor. This provides a means to estimate one of the parameters that characterizes ultracold processes from first principles. The increasing availability of cold and ultracold samples of atoms and molecules has sprung great interest in chemical reactions at very low temperatures [1][2][3][4][5]. Although new experimental approaches [5] appear highly promising, advances in the field are hampered by technical problems in producing most molecules at low temperatures and high enough densities. In contrast to neutral species, ions can be easily trapped and cooled. The technology of Coulomb crystals in radiofrequency ion traps [6] and the possibility of combining them with traps for neutrals or with slow molecular beams [7,8] promise great progress in the analysis of ion-neutral reactions in the near future.Theoretical simulations employing standard ab initio approaches are not feasible for most of the systems thus far considered. For heavy systems (more convenient experimentally) there are no potential energy surfaces (PESs) accurate enough to describe processes near thresholds. Additionally, most of exact dynamical treatments face insurmountable problems in such regimes. However, in contrast to short-range (SR) chemical interactions, those occurring at long range (LR) can be more easily calculated. Moreover, theoretical approaches based only on the knowledge of the LR part of the PES have been able to describe recent experimental findings nearly quantitatively [1,9]. Indeed, processes at very low collision energies favor LR interactions, leading to the idea of universality in extreme cases [10]: the result of the collision depends exclusively on the LR behavior and not on the details of the PES. In this regard, recently proposed LR parametrization procedures [9,[11][12][13] Fitting experimental data, these models are able to predict nonmeasured values providing some insight into the underlying interactions. In particular, the approach by Jachymski et al., based on multichannel quantum-defect theory (MQDT), provides analytical expressions which can be easily compared with experimental data [9,14,15]. The model has been recently applied to a variety of systems [9,16,17]. In particular, for the Penning ionization of Ar by He( 3 S) [5], the rate coefficients have been fitted in a wide range of collision ener...

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On the dynamics of the H++D2(v=,j=)→HD+D+ reaction: A comparison between theory and experiment

Cited by 63 publications

References 53 publications

Effects of the rotational excitation of D2 and of the potential energy surface on the H++D2→HD+D+ reaction

Effects of the rotational excitation of D2 and of the potential energy surface on the H++D2→HD+D+ reaction

Dynamics of the D+ + H2 → HD + H+ reaction at the low energy regime by means of a statistical quantum method

Beyond universality: Parametrizing ultracold complex-mediated reactions using statistical assumptions

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