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

Abstract

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.

Quantum mechanical study of the high-temperature H+ + HD → D+ + H2 reaction for the primordial universe chemistry

“…The scattering wave function is computed up to the hyperradius ρ max = 17.5 a 0 , where the S J v j,v ′ j ′ (E) matrix elements are extracted for many rovibrational levels of the reactant HD and the product H 2 . This method has been successfully applied to the isotopic variants H + + H 2 (Honvault et al 2011b,a;Rao et al 2014;González-Lezana et al 2014;González-Lezana & Honvault 2017), D + + H 2 González-Lezana et al 2013Lara et al 2015) and H + + D 2 (González-Lezana et al 2009). Here we use the VLABP PES calculated by Velilla et al (2008), and which accurately describes the long-range interactions between H + and H 2 .…”

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

“…Since the PES is characterized by a deep well or complex (≈4.5 eV), as illustrated in Fig. 1, rigorous statistical models [23,24] have been applied to this reaction and isotopic variants in the low and thermal energy regimes [20,[24][25][26][27] in good agreement with accurate …”

Ortho–para-H2conversion processes in astrophysical media

“…However, in contrast with the isotopic variant D + + H 2 [53,54,63] where the same PES is used, the H + + H 2 system offers a great advantage, the three identical nuclei which noticeably reduce the CPU time. As already mentioned in the previous Section the corresponding PES has a deep well and thus many states have to be taken into account in the CC equations.…”