Quantum mechanical calculation of product state distributions for the O(1D)+H2→OH+H reaction on the ground electronic state surface

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Reaction cross sections for the H+D 2 (ν 0 =1)→HD+D and D+H 2 (ν 0 =1)→DH+H systems. A multiconfiguration time-dependent Hartree (MCTDH) wave packet propagation study J. Chem. Phys. 116, 10641 (2002) State-to-state differential cross sections have been calculated for the hydrogen exchange reaction, H+H 2 → H 2 + H, using five different high quality potential energy surfaces with the objective of examining the sensitivity of these detailed cross sections to the underlying potential energy surfaces. The calculations were performed using a new parallel computer code, DIFFREALWAVE. The code is based on the real wavepacket approach of Gray and Balint-Kurti ͓J. Chem. Phys. 108, 950 ͑1998͔͒. The calculations are parallelized over the helicity quantum number ⍀Ј ͑i.e., the quantum number for the body-fixed z component of the total angular momentum͒ and wavepackets for each J , ⍀Ј set are assigned to different processors, similar in spirit to the Coriolis-coupled processors approach of Goldfield and Gray ͓Comput. Phys. Commun. 84, 1 ͑1996͔͒. Calculations for J =0-24 have been performed to obtain converged state-to-state differential cross sections in the energy range from 0.4 to 1.2 eV. The calculations employ five different potential energy surfaces, the BKMP2 surface and a hierarchical family of four new ab initio surfaces ͓S. L. Mielke, et al., J. Chem. Phys. 116, 4142 ͑2002͔͒. This family of four surfaces has been calculated using three different hierarchical sets of basis functions and also an extrapolation to the complete basis set limit, the so called CCI surface. The CCI surface is the most accurate surface for the H 3 system reported to date. Our calculations of differential cross sections are the first to be reported for the A2, A3, A4, and CCI surfaces. They show that there are some small differences in the cross sections obtained from the five different surfaces, particularly at higher energies. The calculations also show that the BKMP2 performs well and gives cross sections in very good agreement with the results from the CCI surface, displaying only small divergences at higher energies.

Section: Theorymentioning

confidence: 99%

Section: Transformation To Product Jacobi Coordinatesmentioning

confidence: 99%

State-to-state reactive differential cross sections for the H+H2→H2+H reaction on five different potential energy surfaces employing a new quantum wavepacket computer code: DIFFREALWAVE

Hankel

Smith²,

Allan³

et al. 2006

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“…Chebyshev and split-operator propagators are the two most commonly used schemes in the RPD method. [29][30][31][32] The Chebyshev real wavepacket method [33][34][35][36][37][38][39] usually employs product Jacobi coordinates to evolve the real part of the wavepacket with Chebyshev iterations, thus providing an efficient and convenient approach to the calculation of S ͑scattering͒ matrix elements.…”

Section: Introductionmentioning

confidence: 99%

“…In state-of-the-art theory, in addition to the timeindependent quantum mechanical approaches, 27,28 timedependent wavepacket quantum methods such as the reactant-product decoupling ͑RPD͒ method, [29][30][31][32] the Chebyshev real wavepacket method, [33][34][35][36][37][38][39] the coordinate transformation method, 40 etc., have been developed and applied in the recent state-to-state calculations on triatomic systems. The RPD approaches [29][30][31][32] introduce partitioning/absorbing potentials which decouple the Schrödinger equation.…”

Section: Introductionmentioning

confidence: 99%

Coriolis coupling effects in the calculation of state-to-state integral and differential cross sections for the H+D2 reaction

Chu

Han

Hankel

et al. 2007

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State-to-state reactive differential cross sections for the H + H 2 → H 2 + H reaction on five different potential energy surfaces employing a new quantum wavepacket computer code: DIFFREALWAVE J. Chem. Phys. 125, 164303 (2006) The quantum wavepacket parallel computational code DIFFREALWAVE is used to calculate state-to-state integral and differential cross sections for the title reaction on the BKMP2 surface in the total energy range of 0.4-1.2 eV with D 2 initially in its ground vibrational-rotational state. The role of Coriolis couplings in the state-to-state quantum calculations is examined in detail.Comparison of the results from calculations including the full Coriolis coupling and those using the centrifugal sudden approximation demonstrates that both the energy dependence and the angular dependence of the calculated cross sections are extremely sensitive to the Coriolis coupling, thus emphasizing the importance of including it correctly in an accurate state-to-state calculation.

“…Recently, very efficient real wave packet algorithms have been developed by Gray and Balint-Kurti. 14,15 In their approach, the real part of an evolving wave packet is propagated with a Chebyshev scheme, while all the valuable information ͑e.g., S matrix elements͒ can still be obtained.…”

Section: Introductionmentioning

confidence: 99%

Efficient time-independent wave packet scattering calculations within a Lanczos subspace: H+O2 (J=0) state-to-state reaction probabilities

Zhang

Smith

2002

Erratum: "Comparison of second-order split operator and Chebyshev propagator in wave packet based state-tostate reactive scattering calculations" [J. Chem. Phys.130, 174102 (2009) An efficient Lanczos subspace method has been devised for calculating state-to-state reaction probabilities. The method recasts the time-independent wave packet Lippmann-Schwinger equation ͓Kouri et al., Chem. Phys. Lett. 203, 166 ͑1993͔͒ inside a tridiagonal ͑Lanczos͒ representation in which action of the causal Green's operator is affected easily with a QR algorithm. The method is designed to yield all state-to-state reaction probabilities from a given reactant-channel wave packet using a single Lanczos subspace; the spectral properties of the tridiagonal Hamiltonian allow calculations to be undertaken at arbitrary energies within the spectral range of the initial wave packet. The method is applied to a HϩO 2 system (Jϭ0), and the results indicate the approach is accurate and stable.