A refined H3 potential energy surface

Boothroyd, Arnold I.; Keogh, William J.; Martín, P. G.; Peterson, Michael R.

doi:10.1063/1.471430

Cited by 324 publications

(299 citation statements)

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“…Despite the high symmetry and electronic simplicitytwo-electron system-of the H 3 ϩ ion, only a few ab initio FCI calculations of the global potential energy surfaces ͑GPES͒, including the correct behavior as the molecule dissociates and for all possible geometrical configurations, have been reported for ground (1 1 AЈ 13,14 ͒ and excited (1 3 ⌺ u ϩ , 15 2 1 AЈ 14 ͒ states and for a maximum of 680 different spatial geometries. This fact contrasts with very accurate GPES obtained for more complex polyatomics such as H 3 , with more than 8000 different spatial geometries, 16 H 2 O, 17,18 H 2 F, 19 or H 4 , 20 to name just a few. Moreover, in a recent paper concerning a first attempt on a calculated spectrum for neardissociation H 3 ϩ , Henderson and Tennyson conclude that, in the absence of a high quality global potential, an attack on the global H 3 ϩ problem would be very worthwhile and is easily within the range of present methods.…”

Section: Introductionmentioning

confidence: 76%

“…We have used symmetry group C s for all the geometries and we have computed 36 different states at each point as follows: 9 1 AЈ, 9 1 AЉ, 9 3 AЈ and 9 3 AЉ. To specify our grids of H 3 ϩ conformations, we have adopted the coordinates used by Boothroyd et al 16 in a refined H 3 potential energy surface. These coordinates can be described by the shortest interatomic distance r 1 , the next-shortest distance r 2 , and the exterior angle between them, .…”

Section: Potential Energy Calculationsmentioning

confidence: 99%

“…We have used the preliminary grid described by Boothroyd et al 16 that comprised 540 conformations. Moreover, we have used also the more comprehensive grid that was specified as follows: r 1 and r 2 were chosen from 0.6 to 2.0 a 0 in increments of 0. ran from 0°to 90°i nclusive in increments of 10°and continued from ϭ90°to р120°in one, two, or three equally spaced increments that did not exceed 10°.…”

Section: Potential Energy Calculationsmentioning

confidence: 99%

See 2 more Smart Citations

Potential energy surface and wave packet calculations on the Li+HF→LiF+H reaction

Aguado

Paniagua

Lara

et al. 1997

The Journal of Chemical Physics

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Adiabatic global potential energy surfaces, for singlet and triplet states of AЈ and AЉ symmetries, were computed for an extensive grid for a total of 8469 conformations of H 3 ϩ system at full configuration interaction ab initio level and using an extended basis set that has also been optimized for excited states. An accurate ͑root-mean-square error lower than 20 cm Ϫ1 ) global fit to the ground-state potential is obtained using a diatomics-in-molecules approach corrected by several symmetrized three-body terms with a total of 96 linear parameters and 3 nonlinear parameters. This produces an accurate global potential which represents all aspects of ground-state H 3 ϩ including the absolute minimum, the avoided crossing and dissociation limits, satisfying the correct symmetry properties of the system. The rovibrational eigenstates have been calculated up to total angular momentum Jϭ20 using hyperspherical coordinates with symmetry adapted basis functions. The infrared spectra thus reproduced is within 1 cm Ϫ1 with respect to the experimental values for several transitions.

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Section: Introductionmentioning

confidence: 76%

Section: Potential Energy Calculationsmentioning

confidence: 99%

Section: Potential Energy Calculationsmentioning

confidence: 99%

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Potential energy surface and wave packet calculations on the Li+HF→LiF+H reaction

Aguado

Paniagua

Lara

et al. 1997

The Journal of Chemical Physics

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“…As mentioned above, the behaviour with collision energy and the magnitudes of the cross sections relate to the v 2 term in the expansion of the interaction potential. For scattering at low energies, the region R ∼ > 4 a 0 is relevant, where the v 2 coefficient calculated by Mielke et al [1] is in distinctly better agreement with that of Partridge et al [4] than that of Boothroyd et al [3]. Consequently, it was not surprising to find that the cross sections which derive from potentials [1] and [4] are also in better agreement.…”

mentioning

confidence: 73%

A quantum-mechanical study of rotational transitions in H₂induced by H

Wrathmall¹,

Flower²

2006

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. Cross sections have been computed for rotational transitions of H 2 , induced by collisions with H atoms, using a recent H -H 2 potential calculated by Mielke et al. [1]. These results are compared with those obtained with earlier potentials. Significant discrepancies are found with results deriving from the potential of Boothroyd et al. [3] in the low collision energy regime. We compare also cross sections derived using different levels of approximation to the vibrational motion.The H -H 2 atom-molecule system is the simplest triatomic system; but, in spite of its structural simplicity, it has proved difficult to calculate the interaction potential to an accuracy which is sufficient to determine reliably the rotational excitation cross sections near threshold. In the regime of collision energies E ∼ < 5000 K, a potential barrier inhibits H-atom exchange scattering, and rotational excitation of the molecule occurs predominantly through non-exchange scattering; at higher energies, exchangescattering occurs also. These processes contribute to the excitation of H 2 in the interstellar medium, notably in jets associated with star formation. Pure rotational transitions of H 2 have been observed from levels up to v = 0, J = 27 (Rosenthal et al. A recent study of the H -H 2 potential by Mielke et al.[1] appears to have improved on the accuracy of earlier work by Boothroyd et al. [3] and Partridge et al. [4]. Whilst all these calculations agree with regard to the general features of the potential, which becomes repulsive at short range and displays only a shallow Van der Waals minimum of approximately 2 meV (20 K), there remain significant differences in the predicted anisotropy of the potential; and it is the anisotropy which determines the magnitude of the rotationally inelastic cross sections. In this Letter, we present the results of calculations of cross sections for rotational transitions within the v = 0 vibrational ground state of H 2 , comparing the values obtained using different determinations of the H -H 2 interaction potential.When determining the rotational excitation cross sections, it is customary to expand the interaction potential V (R, θ, r), in terms of Legendre polynomials, P λ (cos θ), V (R, θ, r) = ∞ λ=0 v λ (R, r)P λ (cos θ),

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“…The calculations have been performed by employing a BKMP2 surface. 36 Figure 1 shows the state-to-state DCS as a function of total energy for two scattering angles of θ = 0 and 90°for the rovibrational state v = 0, 1 and j = 0, 2, 4, 6. Clearly, all of the wavepacket DCSs in Figure 1 are in perfect agreement with TID results over the entire energy range.…”

Section: Et Fmentioning

confidence: 99%

Adiabatic/Nonadiabatic State-to-State Reactive Scattering Dynamics Implemented on Graphics Processing Units

Zhang

Han

2013

J. Phys. Chem. A

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An efficient graphics processing units (GPUs) version of time-dependent wavepacket code is developed for the atom−diatom state-to-state reactive scattering processes. The propagation of the wavepacket is entirely calculated on GPUs employing the split-operator method after preparation of the initial wavepacket on the central processing unit (CPU). An additional split-operator method is introduced in the rotational part of the Hamiltonian to decrease communication of GPUs without losing accuracy of state-to-state information. The code is tested to calculate the differential cross sections of H + H 2 reaction and state-resolved reaction probabilities of nonadiabatic triplet−singlet transitions of O( 3 P, 1 D) + H 2 for the total angular momentum J = 0. The global speedups of 22.11, 38.80, and 44.80 are found comparing the parallel computation of one GPU, two GPUs by exact rotational operator, and two GPU versions by an approximate rotational operator with serial computation of the CPU, respectively. INTRODUCTIONA state-to-state quantum reaction dynamics study provides the most detailed observables and offers profound insight of chemical reaction process. In the past decades, several approaches for quantum reaction dynamics have been developed. With hyperspherical coordinate, the time-independent (TID) coupled-channel method has been employed to study many triatomic systems. 1,2 On the other hand, the timedependent method has been wildly used and implemented by different schemes because it does not scale as a cube of the number of basis functions. The coordinates can be chosen as reactant Jacobi, product Jacobi, or hyperspherical coordinates. 3−5 The wavepacket can be real or complex 6,7 and be propagated by the split-operator method, 8,9 Chebyshev polynomial expansion, finite difference approaches, and so forth. 10,11 While the calculations of differential cross sections (DCSs) have been reported for many triatomic reactions and two tetraatomic systems up to now, 12 theoretical calculations are still a great challenge of computational time consumption. Thus, the parallelism on central processing units (CPUs) has become a routine for state-resolved quantum dynamics. Because largescale parallelism with hundreds of computational nodes is still expensive, parallelism on graphics processing units (GPUs) provides a good alternative for being able to access hundreds of cores in the single GPU. The GPU has been widely used in many traditional computational scientific areas. As to chemistry science, one GPU provides hundreds of times the performance of a single CPU core in molecular dynamics and electronic structure calculations. 13,14 Recently, the CPUs/GPUs implemented in the TID method show a 6.98 speedup obtained by three GPUs and three CPU cores on computational efficiency. 15 Pacifici et al. have reported a GPU implementation for reactive scattering through the evaluation of the reactive

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A refined H3 potential energy surface

Cited by 324 publications

References 26 publications

Potential energy surface and wave packet calculations on the Li+HF→LiF+H reaction

Potential energy surface and wave packet calculations on the Li+HF→LiF+H reaction

A quantum-mechanical study of rotational transitions in H₂induced by H

Adiabatic/Nonadiabatic State-to-State Reactive Scattering Dynamics Implemented on Graphics Processing Units

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A refined H3 potential energy surface

Cited by 324 publications

References 26 publications

Potential energy surface and wave packet calculations on the Li+HF→LiF+H reaction

Potential energy surface and wave packet calculations on the Li+HF→LiF+H reaction

A quantum-mechanical study of rotational transitions in H2induced by H

Adiabatic/Nonadiabatic State-to-State Reactive Scattering Dynamics Implemented on Graphics Processing Units

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A quantum-mechanical study of rotational transitions in H₂induced by H