Molecular beam and trajectory studies of reactions of H+ with H2

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.

Section: Introductionmentioning

confidence: 75%

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

“…It is generally understood that as the energy increases the process evolves from a complex-forming pathway to a direct reaction. 20,23,40,41 In those earlier works this transition between different dynamical mechanisms has been observed at the onset of the charge-transfer channels which become energetically open after the electronic crossing mentioned above. 9,26 In more recent studies on the H + +D 2 and D + +H 2 reactions the deviation of the statistical predictions obtained with a statistical quasiclassical trajectory (SQCT) approach with respect to QM results are observed at much lower energies.…”

Section: Introductionmentioning

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 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.

“…Early calculations starting in the seventies [45][46][47][48][49] disclosed the main characteristics of its mechanism that evolves from a low energy behavior, dominated by capture into a strongly interacting complex, to a higher energy behavior characterized by more direct collisions. Under these circumstances, shorter interaction times do not allow for a complete randomization of the energy, angular momentum, and nuclear scrambling within the reaction intermediate.…”

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

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