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Wang R, Zhao H, Sun Z. Reactant-Product Decoupling Technique Using the Intermediate Coordinate Method. J Phys Chem A 2024; 128:3726-3741. [PMID: 38666315 DOI: 10.1021/acs.jpca.4c01148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Although the reactant-product decoupling (RPD) technique was proposed over two decades ago, it remains an efficient approach for calculating product state-resolved information on some simple direct reactions using the quantum wave packet method. In the past, usually the RPD technique employed the collocation method to transform the wave function between reactant and product arrangements, which requires quite large computational efforts. In this work, the intermediate coordinate (IC) method is employed to realize the RPD technique. Numerical examples demonstrate that this new IC RPD (IRPD) technique has superior computational efficiency compared with the original method employing the collocation method. Especially, the new IRPD technique significantly saves disk space and computer memory. To illustrate the features of our new method, the total reaction probabilities of the H + H2, H + Br2, and F + H2 reactions with J = 0 and the differential cross sections of the H + H2 and F + H2 reactions at a series of collision energy are calculated and presented. With this efficient and effective new RPD technique, the Li + HF reaction, which involves sharp resonances with long-range wave functions in the van der Waals wells in both the reactant and product arrangements, is also calculated with several J at the product state-resolved level to reveal the ability of the RPD technique for describing resonance wave functions. With these numerical examples, it is found that, for the reaction with resonances, the RPD approach should be applied carefully. Otherwise, it is very possible that the resonances could disappear with the application of the RPD technique.
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Affiliation(s)
- Ransheng Wang
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hailin Zhao
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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2
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Buren B, Chen M, Sun Z, Guo H. Quantum Wave Packet Treatment of Cold Nonadiabatic Reactive Scattering at the State-To-State Level. J Phys Chem A 2021; 125:10111-10120. [PMID: 34767377 DOI: 10.1021/acs.jpca.1c08105] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cold and ultracold collisions are dominated by quantum effects, such as resonances, tunneling, and nonadiabatic transitions between different electronic states. Due to the extremely long de Broglie wavelength in such processes, quantum reactive scattering is most conveniently characterized using the time-independent close-coupling (TICC) methods. However, the TICC approach is difficult for systems with a large number of channels because of its steep numerical scaling laws. Here, a recently proposed quantum wave packet (WP) approach for solving adiabatic reactive scattering problems at low collision energies is extended to include nonadiabatic transitions. To impose the outgoing boundary conditions, the total scattering wavefunction is split into three parts, the interaction, the asymptotic, and the long-range regions. Each region is associated with a different set of basis functions, which could be optimized separately. In this way, an extremely long grid can be used to accommodate the characteristic long de Broglie wavelengths in the scattering coordinate. The better numerical scaling laws of the WP approach have the potential for handling larger nonadiabatic reactive systems at low temperatures in the future.
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Affiliation(s)
- Bayaer Buren
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China.,Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Maodu Chen
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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3
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Manzhos S, Carrington T. Neural Network Potential Energy Surfaces for Small Molecules and Reactions. Chem Rev 2020; 121:10187-10217. [PMID: 33021368 DOI: 10.1021/acs.chemrev.0c00665] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We review progress in neural network (NN)-based methods for the construction of interatomic potentials from discrete samples (such as ab initio energies) for applications in classical and quantum dynamics including reaction dynamics and computational spectroscopy. The main focus is on methods for building molecular potential energy surfaces (PES) in internal coordinates that explicitly include all many-body contributions, even though some of the methods we review limit the degree of coupling, due either to a desire to limit computational cost or to limited data. Explicit and direct treatment of all many-body contributions is only practical for sufficiently small molecules, which are therefore our primary focus. This includes small molecules on surfaces. We consider direct, single NN PES fitting as well as more complex methods that impose structure (such as a multibody representation) on the PES function, either through the architecture of one NN or by using multiple NNs. We show how NNs are effective in building representations with low-dimensional functions including dimensionality reduction. We consider NN-based approaches to build PESs in the sums-of-product form important for quantum dynamics, ways to treat symmetry, and issues related to sampling data distributions and the relation between PES errors and errors in observables. We highlight combinations of NNs with other ideas such as permutationally invariant polynomials or sums of environment-dependent atomic contributions, which have recently emerged as powerful tools for building highly accurate PESs for relatively large molecular and reactive systems.
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Affiliation(s)
- Sergei Manzhos
- Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, 1650, Boulevard Lionel-Boulet, Varennes, Québec City, Québec J3X 1S2, Canada
| | - Tucker Carrington
- Chemistry Department, Queen's University, Kingston Ontario K7L 3N6, Canada
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Guan Y, Zhang DH, Guo H, Yarkony DR. Representation of coupled adiabatic potential energy surfaces using neural network based quasi-diabatic Hamiltonians: 1,2 2A′ states of LiFH. Phys Chem Chem Phys 2019; 21:14205-14213. [DOI: 10.1039/c8cp06598e] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A general algorithm for determining diabatic representations from adiabatic energies, energy gradients and derivative couplings using neural networks is introduced.
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Affiliation(s)
- Yafu Guan
- Department of Chemistry
- Johns Hopkins University
- Baltimore
- USA
| | - Dong H. Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian 116023
- People's Republic of China
| | - Hua Guo
- Department of Chemistry and Chemical Biology
- University of New Mexico
- Albuquerque
- USA
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5
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Xie C, Liu X, Guo H. State-to-state quantum dynamics of the H + LiF → Li + HF reaction on an accurate ab initio potential energy surface. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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6
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Liu X, Xie C, Guo H. A new potential energy surface and state-to-state quantum dynamics of the Li + HF → H + LiF reaction. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.01.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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7
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Guan Y, Fu B, Zhang DH. Construction of diabatic energy surfaces for LiFH with artificial neural networks. J Chem Phys 2017; 147:224307. [DOI: 10.1063/1.5007031] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yafu Guan
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People’s Republic of China
| | - Bina Fu
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People’s Republic of China
| | - Dong H. Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People’s Republic of China
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8
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Tan RS, Zhai HC, Yan W, Gao F, Lin SY. A new ab initio potential energy surface of LiClH (1A') system and quantum dynamics calculation for Li + HCl (v = 0, j = 0-2) → LiCl + H reaction. J Chem Phys 2017; 146:164305. [PMID: 28456188 DOI: 10.1063/1.4982066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A new ab initio potential energy surface (PES) for the ground state of Li + HCl reactive system has been constructed by three-dimensional cubic spline interpolation of 36 654 ab initio points computed at the MRCI+Q/aug-cc-pV5Z level of theory. The title reaction is found to be exothermic by 5.63 kcal/mol (9 kcal/mol with zero point energy corrections), which is very close to the experimental data. The barrier height, which is 2.99 kcal/mol (0.93 kcal/mol for the vibrationally adiabatic barrier height), and the depth of van der Waals minimum located near the entrance channel are also in excellent agreement with the experimental findings. This study also identified two more van der Waals minima. The integral cross sections, rate constants, and their dependence on initial rotational states are calculated using an exact quantum wave packet method on the new PES. They are also in excellent agreement with the experimental measurements.
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Affiliation(s)
- Rui Shan Tan
- School of Physics, Shandong University, Jinan 250100, China
| | - Huan Chen Zhai
- School of Physics, Shandong University, Jinan 250100, China
| | - Wei Yan
- School of Physics, Shandong University, Jinan 250100, China
| | - Feng Gao
- School of Physics, Shandong University, Jinan 250100, China
| | - Shi Ying Lin
- School of Physics, Shandong University, Jinan 250100, China
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9
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Li WT, Chen MD, Sun ZG. Quantum Dynamics of Li+HF/DF Reaction Investigated by a State-to-State Time-dependent Wave Packet Approach. CHINESE J CHEM PHYS 2015. [DOI: 10.1063/1674-0068/28/cjcp1507151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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10
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He X, Chao (Wu) VWK, Han K, Hao C, Zhang Y. Mechanism of the collision energy and reagent vibration’s effects on the collision time for the reaction Ca+HCl. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2014.12.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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12
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Yang KR, Xu X, Truhlar DG. Direct diabatization of electronic states by the fourfold-way: Including dynamical correlation by multi-configuration quasidegenerate perturbation theory with complete active space self-consistent-field diabatic molecular orbitals. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.04.036] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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Fan Q, Li H, Feng H, Sun W, Lu T, Simmonett AC, Xie Y, Schaefer HF. New Potential Energy Surface Features for the Li + HF → LiF + H Reaction. J Phys Chem A 2013; 117:10027-33. [DOI: 10.1021/jp400541a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qunchao Fan
- Research Center for Advanced
Computation, School of Physics and Chemistry, Xihua University, Chengdu, Sichuan, China 610039
| | - Huidong Li
- Research Center for Advanced
Computation, School of Physics and Chemistry, Xihua University, Chengdu, Sichuan, China 610039
| | - Hao Feng
- Research Center for Advanced
Computation, School of Physics and Chemistry, Xihua University, Chengdu, Sichuan, China 610039
| | - Weiguo Sun
- Research Center for Advanced
Computation, School of Physics and Chemistry, Xihua University, Chengdu, Sichuan, China 610039
| | - Tongxiang Lu
- Center for Computational Quantum
Chemistry, University of Georgia, Athens,
Georgia 30602, United States
| | - Andrew C. Simmonett
- Center for Computational Quantum
Chemistry, University of Georgia, Athens,
Georgia 30602, United States
| | - Yaoming Xie
- Center for Computational Quantum
Chemistry, University of Georgia, Athens,
Georgia 30602, United States
| | - Henry F. Schaefer
- Center for Computational Quantum
Chemistry, University of Georgia, Athens,
Georgia 30602, United States
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14
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CHENG JIE, YUE XIANFANG. QUASICLASSICAL TRAJECTORY STUDY OF STEREODYNAMICS FOR THE REACTIONS Li+ HF/DF/TF. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2013. [DOI: 10.1142/s0219633613500089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Stereodynamics of the reaction Li + HF (v = 0,j = 0) → LiF + H and its isotopic variants on the ground electronic state (12A′) potential energy surface (PES) are studied by employing the quasiclassical trajectory (QCT) method. At a collision energy of 2.2 kcal/mol, product rotational angular momentum distributions, P(θr) and P(ϕr), are calculated in the center-of-mass (CM) frame. The results demonstrate that the product rotational angular momentum j′ is not only aligned along the direction perpendicular to the reagent relative velocity vector k, but also oriented along the negative y-axis. The four generalized polarization-dependent differential cross sections (PDDCSs) are also computed. The PDDCS00 distribution shows a sideways scattering for the reaction Li + HF and a strongly backward scattering for the reaction Li + DF . However, it displays both the forward and backward scatterings for the reaction Li + TF . These features demonstrate that the Li + HF and Li + DF reactions proceed predominantly through the direct reaction mechanism. However, the Li + TF reaction undergoes both the direct and indirect reaction mechanisms. The PDDCS21- distribution indicates that the product angular distributions are anisotropic.
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Affiliation(s)
- JIE CHENG
- Department of Physics and Information Engineering, Jining University, Qufu 273155, P. R. China
| | - XIAN-FANG YUE
- Department of Physics and Information Engineering, Jining University, Qufu 273155, P. R. China
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15
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Yue XF, Wang MS. Isotope effects on product polarization and reaction mechanism in the Li+HF(v=0,j=0)→LiF+H reaction. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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Bobbenkamp R, Loesch H, Mudrich M, Stienkemeier F. The excitation function for Li + HF → LiF + H at collision energies below 80 meV. J Chem Phys 2011; 135:204306. [DOI: 10.1063/1.3664303] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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González-Sánchez L, Vasyutinskii O, Zanchet A, Sanz-Sanz C, Roncero O. Quantum stereodynamics of Li + HF reactive collisions: the role of reactants polarization on the differential cross section. Phys Chem Chem Phys 2011; 13:13656-69. [DOI: 10.1039/c0cp02452j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Zanchet A, Roncero O, González-Lezana T, Rodríguez-López A, Aguado A, Sanz-Sanz C, Gómez-Carrasco S. Differential Cross Sections and Product Rotational Polarization in A + BC Reactions Using Wave Packet Methods: H+ + D2 and Li + HF Examples. J Phys Chem A 2009; 113:14488-501. [DOI: 10.1021/jp9038946] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Zanchet
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - O. Roncero
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - T. González-Lezana
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - A. Rodríguez-López
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - A. Aguado
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - C. Sanz-Sanz
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - S. Gómez-Carrasco
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
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19
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Mota VC, Varandas AJC. HN2(2A‘) Electronic Manifold. II. Ab Initio Based Double-Sheeted DMBE Potential Energy Surface via a Global Diabatization Angle. J Phys Chem A 2008; 112:3768-86. [DOI: 10.1021/jp710610d] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vinícius C. Mota
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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20
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Mestdagh JM, Spiegelman F, Gloaguen E, Collier M, Lepetit F, Gaveau MA, Sanz CS, Soep B. Transition State Spectroscopy of the Photoinduced Ca + CH3F Reaction. 2. Experimental and Ab Initio Studies of the Free Ca···FCH3 Complex. J Phys Chem A 2006; 110:7355-63. [PMID: 16759123 DOI: 10.1021/jp057483j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Ca* + CH3F --> CaF + CH3 reaction was photoinduced in 1:1 Ca...CH3F complexes formed in a supersonic expansion. The transition state of the reaction was explored by monitoring the electronically excited product, CaF, while scanning the laser that turns on the reaction. Moreover, the electronic structure of the Ca...FCH3 system was studied using ab initio methods by associating a pseudopotential description of the [Ca2+] and [F7+] cores, a core polarization operator on calcium, an extensive Gaussian basis and a treatment of the electronic problem at the CCSD(T) (ground state) and RSPT2 (excited states) level. In this contribution we present experimental results for the free complex and a comparison with the results of a previous experiment where the Ca...CH3F complexes are deposited at the surface of large argon clusters. The ab initio calculations allowed an interpretation of the experimental data in terms of two reaction mechanisms, one involving a partial charge transfer state, the other involving the excitation of the C-F stretch in the CH3F moiety prior to charge transfer.
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Affiliation(s)
- J-M Mestdagh
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/DRECAM/Service des Photons, Atomes et Molécules, CEA Saclay, F-91191 Gif-sur-Yvette Cedex, France
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21
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Bobbenkamp R, Paladini A, Russo A, Loesch HJ, Menéndez M, Verdasco E, Aoiz FJ, Werner HJ. Effect of rotational energy on the reaction Li+HF(υ=0,j)→LiF+H: An experimental and computational study. J Chem Phys 2005; 122:244304. [PMID: 16035754 DOI: 10.1063/1.1942496] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In a crossed molecular-beam study we have measured angular and time-of-flight distributions of the product LiF from the reaction Li + HF(upsilon = 0)-->LiF + H at various collision energies ranging from 97 to 363 meV for three markedly different rotational state distributions of HF obtained at nozzle temperatures close to 315, 510, and 850 K. Particularly, for the low and intermediate collision energies we observe significant effects of the varying j-state populations on the shape of the product angular distributions. At 315 K an additional feature appears in the angular distributions which is interpreted as being due to scattering from HF dimers. The experimental data are compared with simulations of the monomer reaction based on extensive quasiclassical trajectory calculations on a new state-of-the-art ab initio potential energy surface. We find an overall good agreement between the theoretical simulations and the experimental data for the title reaction, especially at the highest HF nozzle temperature.
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22
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Weck PF, Balakrishnan N. Heavy atom tunneling in chemical reactions: Study of H+LiF collisions. J Chem Phys 2005; 122:234310. [PMID: 16008444 DOI: 10.1063/1.1930847] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The H+LiF(X (1)sigma(+),upsilon=0-2,j=0)-->HF(X (1)sigma(+),upsilon',j')+Li(2S) bimolecular process is investigated by means of quantum scattering calculations on the chemically accurate X 2A' LiHF potential energy surface of Aguado et al. [A. Aguado, M. Paniagua, C. Sanz, and J. Roncero, J. Chem. Phys. 119, 10088 (2003)]. Calculations have been performed for zero total angular momentum for translational energies from 10(-7) to 10(-1) eV. Initial-state selected reaction probabilities and cross sections are characterized by resonances originating from the decay of metastable states of the H...F-Li and Li...F-H van der Waals complexes. Extensive assignment of the resonances has been carried out by performing quasibound states calculations in the entrance and exit channel wells. Chemical reactivity is found to be significantly enhanced by vibrational excitation at low temperatures, although reactivity appears much less favorable than nonreactive processes due to the inefficient tunneling of the relatively heavy fluorine atom strongly bound in van der Waals complexes.
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Affiliation(s)
- P F Weck
- Department of Chemistry, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154, USA.
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23
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Verbockhaven G, Sanz C, Groenenboom GC, Roncero O, van der Avoird A. Ab initiopotential-energy surface for the reaction Ca+HCl→CaCl+H. J Chem Phys 2005; 122:204307. [PMID: 15945724 DOI: 10.1063/1.1899154] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The potential-energy surface of the ground electronic state of CaHCl has been obtained from 6400 ab initio points calculated at the multireference configuration-interaction level and represented by a global analytical fit. The Ca+HCl-->CaCl+H reaction is endothermic by 5100 cm(-1) with a barrier of 4470 cm(-1) at bent geometry, taking the zero energy in the Ca+HCl asymptote. On both sides of this barrier are potential wells at linear geometries, a shallow one due to van der Waals interactions in the entrance channel, and a deep one attributed to the H(-)Ca(++)Cl(-) ionic configuration. The accuracy of the van der Waals well depth, approximately 200 cm(-1), was checked by means of additional calculations at the coupled-cluster singles and doubles with perturbative triples level and it was concluded that previous empirical estimates are unrealistic. Also, the electric dipole function was calculated, analytically fitted in the regions of the two wells, and used to analyze the charge shifts along the reaction path. In the insertion well, 16,800 cm(-1) deep, the electric dipole function confirmed the ionic structure of the HCaCl complex and served to estimate effective atomic charges. Finally, bound rovibrational levels were computed both in the van der Waals well and in the insertion well, and the infrared-absorption spectrum of the insertion complex was simulated in order to facilitate its detection.
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Affiliation(s)
- Gilles Verbockhaven
- Institute of Theoretical Chemistry, Institute for Molecules and Materials, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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Weck PF, Balakrishnan N. Quantum dynamics of the Li+HF→H+LiF reaction at ultralow temperatures. J Chem Phys 2005; 122:154309. [PMID: 15945637 DOI: 10.1063/1.1884115] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantum-mechanical calculations are reported for the Li+HF(v=0,1,j=0)-->H+LiF(v',j') bimolecular scattering process at low and ultralow temperatures. Calculations have been performed for zero total angular momentum using a recent high-accuracy potential-energy surface for the X2A' electronic ground state. For Li+HF(v=0,j=0), the reaction is dominated by resonances due to the decay of metastable states of the Li cdots,...F-H van der Waals complex. Assignment of these resonances has been carried out by calculating the eigenenergies of the quasibound states. We also find that while chemical reactivity is greatly enhanced by vibrational excitation, the resonances get mostly washed out in the reaction of vibrationally excited HF with Li atoms. In addition, we find that at low energies, the reaction is significantly suppressed due to the less-efficient tunneling of the relatively heavy fluorine atom.
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Affiliation(s)
- P F Weck
- Department of Chemistry, University of Nevada Las Vegas, Las Vegas, Nevada 89154, USA.
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Jasper AW, Truhlar DG. Conical intersections and semiclassical trajectories: Comparison to accurate quantum dynamics and analyses of the trajectories. J Chem Phys 2005; 122:44101. [PMID: 15740229 DOI: 10.1063/1.1829031] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Semiclassical trajectory methods are tested for electronically nonadiabatic systems with conical intersections. Five triatomic model systems are presented, and each system features two electronic states that intersect via a seam of conical intersections (CIs). Fully converged, full-dimensional quantum mechanical scattering calculations are carried out for all five systems at energies that allow for electronic de-excitation via the seam of CIs. Several semiclassical trajectory methods are tested against the accurate quantum mechanical results. For four of the five model systems, the diabatic representation is the preferred (most accurate) representation for semiclassical trajectories, as correctly predicted by the Calaveras County criterion. Four surface hopping methods are tested and have overall relative errors of 40%-60%. The semiclassical Ehrenfest method has an overall error of 66%, and the self-consistent decay of mixing (SCDM) and coherent switches with decay of mixing (CSDM) methods are the most accurate methods overall with relative errors of approximately 32%. Furthermore, the CSDM method is less representation dependent than both the SCDM and the surface hopping methods, making it the preferred semiclassical trajectory method. Finally, the behavior of semiclassical trajectories near conical intersections is discussed.
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Affiliation(s)
- Ahren W Jasper
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431, USA
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Höbel O, Bobbenkamp R, Paladini A, Russo A, Loesch HJ. Effect of translational energy on the reaction Li + HF(v = 0) → LiF + H. Phys Chem Chem Phys 2004. [DOI: 10.1039/b400926f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Aguado A, Paniagua M, Sanz C, Roncero O. Transition state spectroscopy of the excited electronic states of Li–HF. J Chem Phys 2003. [DOI: 10.1063/1.1618223] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wei L, Jasper AW, Truhlar DG. Narrow Subthreshold Quantum Mechanical Resonances in the Li + HF → H + LiF Reaction. J Phys Chem A 2003. [DOI: 10.1021/jp0345250] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Liqiang Wei
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
| | - Ahren W. Jasper
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
| | - Donald G. Truhlar
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
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Troisi A, Orlandi G. Construction of electronic diabatic states within a molecular orbital scheme. J Chem Phys 2003. [DOI: 10.1063/1.1555118] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Nakamura H, Truhlar DG. Direct diabatization of electronic states by the fourfold way. II. Dynamical correlation and rearrangement processes. J Chem Phys 2002. [DOI: 10.1063/1.1500734] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bound and quasi-bound states of the Li⋯FH van der Waals molecule: The effects of the potential energy surface and of the basis set superposition error. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0166-1280(02)00219-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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