1
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Mao Y, Chen H, Yang Z, Buren B, Chen M. Stereodynamic control of nonadiabatic processes in low-energy Be +( 2P) + H 2 ( v = 0, j = 2) collisions. Phys Chem Chem Phys 2024; 26:19812-19821. [PMID: 38988212 DOI: 10.1039/d4cp01996b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
Controlling the relative arrangement of colliding molecules is crucial for determining the dynamical outcomes of chemical processes and has emerged as a hot spot of experimental research. Here, the quantum scattering calculations are conducted to investigate the stereodynamic control in collisions between Be+(2P) and H2 (v = 0, j = 2), which undergo nonadiabatic transitions to the electronic ground state. Stereodynamic preparation is achieved by controlling the initial alignment of the H2 bond axis relative to the scattering frame. For product BeH+ in the reactive process, the differential cross sections (DCSs) are significantly enhanced in the forward and sideways hemispheres when the alignment angle β is 60°. For the product H2 in the quenching channel, the β = 0° preparation can result in a more than one-fold increase in the DCS at a polar scattering angle of 0°. Furthermore, varying the alignment angle β also has noteworthy effects on the rotational-state distributions of BeH+ products. Specifically, β = 0° preparation can induce the disappearance of the bimodal distribution of rotational states at a collision energy of 0.05 eV.
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Affiliation(s)
- Ye Mao
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Hanghang Chen
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Zijiang Yang
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Bayaer Buren
- School of Science, Shenyang University of Technology, Shenyang 110870, P. R. China.
| | - 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, P. R. China.
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2
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Jambrina PG, Croft JFE, Balakrishnan N, Guo H, Aoiz FJ. Determination of collision mechanisms at low energies using four-vector correlations. Faraday Discuss 2024. [PMID: 38836438 DOI: 10.1039/d3fd00173c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
In molecular dynamics, a fundamental question is how the outcome of a collision depends on the relative orientation of the collision partners before their interaction begins (the stereodynamics of the process). The preference for a particular orientation of the reactant complex is intimately related to the idea of a collision mechanism and the possibility of control, as revealed in recent experiments. Indeed, this preference holds not only for chemical reactions involving complex polyatomic molecules, but also for the simplest inelastic atom-diatom collisions at cold collision energies. In this work, we report how the outcome of rotationally inelastic collisions between two D2 molecules can be controlled by changing the alignment of their internuclear axes under the same or different polarization vectors. Our results demonstrate that a higher degree of control can be achieved when two internuclear axes are aligned, especially when both molecules are relaxed in the collision. The possibility of control extends to very low energies, even to the ultracold regime, when no control could be achieved just by the alignment of the internuclear axis of one of the colliding partners.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca 37008, Spain.
| | - J F E Croft
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
| | - N Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
| | - F J Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain.
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3
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Bian X, Subotnik JE. Spin-Dependent Stereochemistry: A Nonadiabatic Quantum Dynamics Case Study of S + H 2 → SH + H Reaction. J Phys Chem Lett 2024:3434-3440. [PMID: 38507592 DOI: 10.1021/acs.jpclett.3c03344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
We study the spin-dependent stereodynamics of the S + H2 → SH + H reaction by using full-dimensional quantum dynamics calculations with zero total nuclear angular momentum along the triplet 3A″ states and singlet 1A' states. We find that the interplay between the electronic spin direction and the molecular geometry has a measurable influence on the singlet-triplet intersystem crossing reaction probabilities. Our results show that for some incident scattering angles in the body-fixed frame, the relative difference in intersystem crossing reaction probabilities (as determined between spin up and spin down initial states) can be as large as 15%. Our findings are an ab initio demonstration of spin-dependent nonadiabatic dynamics, which we hope will shine light as far as understanding the chiral-induced spin selectivity effect.
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Affiliation(s)
- Xuezhi Bian
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joseph E Subotnik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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4
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Veselinova A, Menéndez M, González-Sánchez L, Zanchet A, Aoiz FJ, Jambrina PG. Dynamical effects on the O( 3P) + D 2 reaction and its impact on the Λ-doublet population. Phys Chem Chem Phys 2024; 26:6752-6762. [PMID: 38323460 DOI: 10.1039/d3cp05510h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
The O(3P) + D2 → OD(2Π) + D reaction presents the peculiarity of taking place on two different potential energy surfaces (PESs) of different symmetry, 3A' and 3A'', which become degenerate for collinear configurations where the saddle-point of the reaction is located. The degeneracy is broken for non-collinear approaches with the energy on the 3A' PES rising more abruptly with the bending angle, making the frequency of this mode higher on the 3A' state. Consequently, the 3A' PES should be less reactive than the 3A'' one. Nevertheless, quantum scattering calculations show that the cross section is higher on the 3A' PES for energies close to the classical reaction threshold and rotationless reactant. It is found that the differences between the reactivity on the two PESs are greater for low values of total angular momentum, where the centrifugal barrier is lower and contribute to the higher population of the Π(A') Λ-doublet states of OD at low collision energies. At high collision energies, the Π(A') Λ-doublet state is also preferentially populated. Analysis of the differential cross sections reveals that the preponderance for the Π(A') Λ-doublet at low energies comes from backward scattering, originating from the reaction on the 3A' PES, while at high energies, it proceeds from a different mechanism that leads to sideways scattering on the 3A'' PES and that populates the Π(A') manifold.
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Affiliation(s)
- A Veselinova
- Departamento de Química-Física, Universidad de Salamanca, Salamanca, 37008, Spain.
| | - M Menéndez
- Departamento de Química-Física, Universidad Complutense de Madrid, Madrid, 28040, Spain
| | - L González-Sánchez
- Departamento de Química-Física, Universidad de Salamanca, Salamanca, 37008, Spain.
| | - A Zanchet
- Instituto de Física Fundamental (CSIC), 28006, Madrid, Spain
| | - F J Aoiz
- Departamento de Química-Física, Universidad Complutense de Madrid, Madrid, 28040, Spain
| | - P G Jambrina
- Departamento de Química-Física, Universidad de Salamanca, Salamanca, 37008, Spain.
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5
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Balakrishnan N, Jambrina PG, Croft JFE, Guo H, Aoiz FJ. Quantum stereodynamics of cold molecular collisions. Chem Commun (Camb) 2024; 60:1239-1256. [PMID: 38197484 DOI: 10.1039/d3cc04762h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Advances in quantum state preparations combined with molecular cooling and trapping technologies have enabled unprecedented control of molecular collision dynamics. This progress, achieved over the last two decades, has dramatically improved our understanding of molecular phenomena in the extreme quantum regime characterized by translational temperatures well below a kelvin. In this regime, collision outcomes are dominated by isolated partial waves, quantum threshold and quantum statistics effects, tiny energy splitting at the spin and hyperfine levels, and long-range forces. Collision outcomes are influenced not only by the quantum state preparation of the initial molecular states but also by the polarization of their rotational angular momentum, i.e., stereodynamics of molecular collisions. The Stark-induced adiabatic Raman passage technique developed in the last several years has become a versatile tool to study the stereodynamics of light molecular collisions in which alignment of the molecular bond axis relative to initial collision velocity can be fully controlled. Landmark experiments reported by Zare and coworkers have motivated new theoretical developments, including formalisms to describe four-vector correlations in molecular collisions that are revealed by the experiments. In this Feature article, we provide an overview of recent theoretical developments for the description of stereodynamics of cold molecular collisions and their implications to cold controlled chemistry.
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Affiliation(s)
- Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
| | - Pablo G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca 37008, Spain
| | - James F E Croft
- The Dodd Walls Centre for Photonic and Quantum Technologies, New Zealand and Department of Physics, University of Otago, Dunedin, New Zealand
| | - Hua Guo
- Department of Chemistry and Chemical Biology, Center for Computational Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain
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6
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Jambrina PG, Croft JFE, Zuo J, Guo H, Balakrishnan N, Aoiz FJ. Stereodynamical Control of Cold Collisions between Two Aligned D_{2} Molecules. PHYSICAL REVIEW LETTERS 2023; 130:033002. [PMID: 36763383 DOI: 10.1103/physrevlett.130.033002] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/25/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Resonant scattering of optically state-prepared and aligned molecules in the cold regime allows the most detailed interrogation and control of bimolecular collisions. This technique has recently been applied to collisions of two aligned ortho-D_{2} molecules prepared in the j=2 rotational level of the v=2 vibrational manifold using the Stark-induced adiabatic Raman passage technique. Here, we develop the theoretical formalism for describing four-vector correlations in collisions of two aligned molecules and apply our approach to state-prepared D_{2}(v=2,j=2)+D_{2}(v=2,j=2)→D_{2}(v=2,j=2)+D_{2}(v=2,j=0) collisions, making possible the simulations of the experimental results from first principles. Key features of the experimental angular distributions are reproduced and attributed primarily to a partial wave resonance with orbital angular momentum ℓ=4.
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Affiliation(s)
- Pablo G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca 37008, Spain
| | - James F E Croft
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand and Department of Physics, University of Otago, Dunedin 9054, New Zealand
| | - Junxiang Zuo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense. Madrid 28040, Spain
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7
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Wang Y, Huang J, Wang W, Du T, Xie Y, Ma Y, Xiao C, Zhang Z, Zhang DH, Yang X. Stereodynamical control of the H + HD → H 2 + D reaction through HD reagent alignment. Science 2023; 379:191-195. [PMID: 36634162 DOI: 10.1126/science.ade7471] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Prealigning nonpolar reacting molecules leads to large stereodynamical effects because of their weak steering interaction en route to the reaction barrier. However, experimental limitations in preparing aligned molecules efficiently have hindered the investigation of steric effects in bimolecular reactions involving hydrogen. Here, we report a high-resolution crossed-beam study of the reaction H + HD(v = 1, j = 2) → H2(v', j') + D at collision energies of 0.50, 1.20, and 2.07 electron volts in which the vibrationally excited hydrogen deuteride (HD) molecules were prepared in two collision configurations, with their bond preferentially aligned parallel and perpendicular to the relative velocity of collision partners. Notable stereodynamical effects in differential cross sections were observed. Quantum dynamics calculations revealed that strong constructive interference in the perpendicular configuration plays an important role in the stereodynamical effects observed.
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Affiliation(s)
- Yufeng Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Jiayu Huang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Wei Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianyu Du
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yurun Xie
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Department of Chemistry and Shenzhen Key Laboratory of Energy Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuxin Ma
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Hefei National Laboratory, Hefei 230088, China
| | - Zhaojun Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Dong H Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Department of Chemistry and Shenzhen Key Laboratory of Energy Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.,Hefei National Laboratory, Hefei 230088, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Department of Chemistry and Shenzhen Key Laboratory of Energy Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.,Hefei National Laboratory, Hefei 230088, China
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8
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Jambrina PG, Morita M, Croft JFE, Aoiz FJ, Balakrishnan N. Role of Low Energy Resonances in the Stereodynamics of Cold He + D 2 Collisions. J Phys Chem Lett 2022; 13:4064-4072. [PMID: 35499484 DOI: 10.1021/acs.jpclett.2c00587] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In recent experiments using the Stark-induced adiabatic Raman passage technique, Zhou et al. ( J. Chem. Phys. 2021, 154, 104309; Science 2021, 374, 960-964) measured the product's angular distribution for the collisions between He and aligned D2 molecules at cold collision energies. The signatures of the angular distributions were attributed to an [Formula: see text] = 2 resonance that governs scattering at low energies. A first-principles quantum mechanical treatment of this problem is presented here using a highly accurate interaction potential for the He-H2 system. Our results predict a very intense [Formula: see text] = 1 resonance at low energies, leading to angular distributions that differ from those measured in the experiment. A good agreement with the experiment is achieved only when the [Formula: see text] = 1 resonance is artificially removed, for example, by excluding the lowest energies present in the experimental velocity distribution. Our analysis revealed that neither the position nor the intensity of the [Formula: see text] = 1 resonance significantly changes when the interaction potential is modified within its predicted uncertainties. Energy-resolved measurements may help to resolve the discrepancy.
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Affiliation(s)
- Pablo G Jambrina
- Departamento de Química Física, University of Salamanca, Salamanca 37008, Spain
| | - Masato Morita
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States
| | - James F E Croft
- Department of Physics, University of Otago, Dunedin 9054, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand
| | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States
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9
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da Silva H, Kendrick BK, Balakrishnan N. On the use of stereodynamical effects to control cold chemical reactions: The H + D2 ⟷ D + HD case study. J Chem Phys 2022; 156:044305. [DOI: 10.1063/5.0078168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- H. da Silva
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - B. K. Kendrick
- Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - N. Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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10
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Jambrina PG, Croft JFE, Balakrishnan N, Aoiz FJ. Stereodynamic control of cold rotationally inelastic CO + HD collisions. Phys Chem Chem Phys 2021; 23:19364-19374. [PMID: 34524308 DOI: 10.1039/d1cp02755g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Quantum control of molecular collision dynamics is an exciting emerging area of cold collisions. Co-expansion of collision partners in a supersonic molecular beam combined with precise control of their quantum states and alignment/orientation using Stark-induced Adiabatic Raman Passage allows exquisite stereodynamic control of the collision outcome. This approach has recently been demonstrated for rotational quenching of HD in collisions with H2, D2, and He and D2 by He. Here we illustrate this approach for HD(v = 0, j = 2) + CO(v = 0, j = 0) → HD(v' = 0, j') + CO(v' = 0, j') collisions through full-dimensional quantum scattering calculations at collision energies near 1 K. It is shown that the collision dynamics at energies between 0.01-1 K are controlled by an interplay of L = 1 and L = 2 partial wave resonances depending on the final rotational levels of the two molecules. Polarized cross sections resolved into magnetic sub-levels of the initial and final rotational quantum numbers of the two molecules also reveal a significant stereodynamic effect in the cold energy regime. Overall, the stereodynamic effect is controlled by both geometric and dynamical factors, with parity conservation playing an important role in modulating these contributions depending on the particular final state.
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Affiliation(s)
- Pablo G Jambrina
- Departamento de Química Física, University of Salamanca, Salamanca 37008, Spain.
| | - James F E Croft
- Department of Physics, University of Otago, Dunedin 9054, New Zealand. .,Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand
| | | | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain.
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11
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Sáez-Rábanos V, Verdasco JE, Aoiz FJ, Herrero VJ. The F + HD(v = 0, 1; j = 0, 1) reactions: stereodynamical properties of orbiting resonances. Phys Chem Chem Phys 2021; 23:8002-8012. [PMID: 33480905 DOI: 10.1039/d0cp05425a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The excitation functions (reaction cross-section as a function of collision energy) of the F + HD(v = 0, 1; j = 0, 1) benchmark system have been calculated in the 0.01-6 meV collision energy interval using a time-independent hyperspherical quantum dynamics methodology. Special attention has been paid to orbiting resonances, which bring about detailed information on the three-atom interaction during the reactive encounter. The location of the resonances depends on the rovibrational state of the reactants HD(v,j), but is the same for the two product channels HF + D and DF + H, as expected for these resonances that are linked to the van der Waals well at the entrance. The resonance intensities depend both on the entrance and on the exit channels. The peak intensities for the HF + D channel are systematically larger than those for DF + H. Vibrational excitation leads to an increase of the peak intensity by more than an order of magnitude, but rotational excitation has a less drastic effect. It deceases the resonance intensity of the F + HD(v = 1) reaction, but increases somewhat that of F + HD(v = 0). Polarization of the rotational angular momentum with respect to the initial velocity reveals intrinsic directional preferences in the F + HD(v = 0, 1; j = 1) reactions that are manifested in the resonance patterns. The helicities (Ω = 0, Ω = ±1) possible for j = 1 contribute to the resonances, but that from Ω± 1 is, in general, dominant and in some cases exclusive. It corresponds to a preferential alignment of the HD internuclear axis perpendicular to the initial direction of approach and, thus, to side-on collisions. This work also shows that external preparation of the reactants, following the intrinsic preferences, would allow the enhancement or reduction of specific resonance features, and would be of great help for their eventual experimental detection.
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Affiliation(s)
- V Sáez-Rábanos
- Departamento de Sistemas y Recursos Naturales, E.T.S. de Ingeniería de Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040, Madrid, Spain.
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12
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Jambrina PG, González-Sánchez L, Lara M, Menéndez M, Aoiz FJ. Unveiling shape resonances in H + HF collisions at cold energies. Phys Chem Chem Phys 2020; 22:24943-24950. [PMID: 33140788 DOI: 10.1039/d0cp04885b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Scattering resonances are pure quantum effects that appear whenever the collision energy matches the energy of a quasi-bound state of the intermolecular complex. Here we show that rotational quenching of HF(j = 1, 2) with H is strongly influenced by the presence of two resonance peaks, leading to up to a two-fold increase in the thermal rate coefficients at the low temperatures characteristic of the interstellar medium. Our results show that each resonance peak is formed by a cluster of shape resonances, each of them characterized by the same value of the orbital angular momentum but different values of the total angular momentum. The relative intensity of these resonances depends on the relative geometry of the incoming reactants, and our results predict that by changing the alignment of the HF rotational angular momentum it is possible to decompose the resonance peaks, disentangling the underlying resonance pattern and the contribution of different total angular momenta to the resonance.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, University of Salamanca, Salamanca 37008, Spain.
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13
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Morita M, Balakrishnan N. Stereodynamics of ultracold rotationally inelastic collisions. J Chem Phys 2020; 153:184307. [PMID: 33187407 DOI: 10.1063/5.0030808] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent experiments on rotational quenching of HD in the v = 1, j = 2 rovibrational state in collisions with H2, D2, and He near 1 K have revealed strong stereodynamic preference stemming from isolated shape resonances. So far, the experiments and subsequent theoretical analyses have considered the initial HD rotational state in an orientation specified by the projection quantum number m or a coherent superposition of different m states. However, it is known that such stereodynamic control is generally not effective in the ultracold energy regime due to the dominance of the incoming s-wave (l = 0, partial wave). Here, we provide a detailed analysis of the stereodynamics of rotational quenching of HD by He with both m and m' resolution, where m' refers to the inelastically scattered HD. We show the existence of a significant m dependence in the m'-resolved differential and integral cross sections even in the ultracold s-wave regime with a factor greater than 60 for j = 2 → j' = 1 and a factor greater than 1300 for j = 3 → j' = 2 transitions. In the helicity frame, however, the integral cross section has no initial orientation (k) dependence in the ultracold energy regime, even resolving with respect to the final orientation (k'). The distribution of final rotational state orientations (k') is found to be statistical (uniform), regardless of the initial orientation.
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Affiliation(s)
- Masato Morita
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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14
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Pan H, Wang F, Liu K. Multifaceted Stereoselectivity in Polyatomic Reactions. J Phys Chem A 2020; 124:6573-6584. [DOI: 10.1021/acs.jpca.0c04838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Huilin Pan
- Southern University of Science and Technology, Shenzhen, P. R. China 518055
| | - Fengyan Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, P. R. China 200433
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian, P. R. China 116023
- Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan 80424
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15
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Pan H, Liu K. Active stereo-control of the Cl + CH 4(ν 3 = 1) reaction: a three-dimensional perspective. Phys Chem Chem Phys 2020; 22:10949-10956. [PMID: 32377655 DOI: 10.1039/d0cp01502d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transition state in Cl + CH4 is of Cl-H-C collinear geometry. As the reactant CH4 is vibrationally excited by a linearly polarized infrared (IR) light to the antisymmetric-stretching state of ν3 = 1, all four C-H bonds are collectively excited and any one of the H-atoms can be reactive. Yet, a strong alignment of the excited CH4(ν3 = 1), as evidenced from the striking stereo-specificity in the Cl + CH4 reaction, was clearly revealed in a previous, exploratory study. Reported here is the full account of that investigation at two collisional energies of Ec = 4.8 and 2.7 kcal mol-1, using a crossed molecular-beam, product-imaging approach. By active control of the polarization direction of an IR laser under judiciously chosen beam-geometries, a complete set of polarization-dependent differential cross sections is disentangled from the CH3(00) product images. To our surprise, the quantitative results appear nearly identical to those obtained for the isotope-substituted reaction of Cl + CHD3(ν1 = 1) → HCl(ν) + CD3(00). A detailed discussion is presented to elucidate the underlying physics for such an intriguing similarity in stereo-reactivity between a spherical-top and a symmetric-top reactant.
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Affiliation(s)
- Huilin Pan
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10617, Taiwan. and Southern University of Science and Technology, Shenzhen, P. R. China.
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10617, Taiwan. and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China and Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
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16
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Brouard M, Chadwick H, Gordon SDS, Heid CG, Hornung B, Nichols B, Kłos J, Jambrina PG, Aoiz FJ. Differential cross sections and collision-induced rotational alignment in inelastic scattering of NO(X) by Xe. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp2002020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Mark Brouard
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Helen Chadwick
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Sean D. S. Gordon
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Cornelia G. Heid
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Balazs Hornung
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Bethan Nichols
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Pablo G. Jambrina
- Departamento de Química Física, Facultad de Ciencias Químicas, University of Salamanca, Salamanca, Spain
| | - F. Javier Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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17
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Kendrick BK. Nonadiabatic Ultracold Quantum Reactive Scattering of Hydrogen with Vibrationally Excited HD( v = 5-9). J Phys Chem A 2019; 123:9919-9933. [PMID: 31647679 DOI: 10.1021/acs.jpca.9b07318] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The results from electronically non-adiabatic and adiabatic quantum reactive scattering calculations are presented for the H + HD(v = 5-9) → H + HD(v', j') reaction at ultracold collision energies from 10 nK to 60 K. Several experimentally verifiable signatures of the geometric phase are reported in the total and vibrationally and rotationally resolved rate coefficients. Most notable is the predicted 2 orders of magnitude enhancement of the rotationally resolved ultracold rates of odd symmetry relative to those of even symmetry. Prominent shape resonances appear at higher collision energies (100 mK to 20 K), which could be measured experimentally. Significant geometric phase effects are also reported on the resonance energies and lifetimes. In particular, an enhancement (suppression) of the l = 1 (l = 2) shape resonances for HD(v = 5, 6) is predicted for even symmetry relative to those of odd symmetry.
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Affiliation(s)
- Brian K Kendrick
- Theoretical Division , Los Alamos National Laboratory , Group T-1, Mail Stop B221, Los Alamos , New Mexico 87544 , United States
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18
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Jambrina PG, Zanchet A, Menéndez M, Herrero VJ, Aoiz FJ. Unexpected dynamical effects change the lambda-doublet propensity in the tunneling region for the O( 3P) + H 2 reaction. Phys Chem Chem Phys 2019; 21:25389-25396. [PMID: 31709441 DOI: 10.1039/c9cp04690a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One of the most relevant features of the O(3P) + H2 reaction is that it occurs on two different potential energy surfaces (PESs) of symmetries A' and A'' that correlate reactants and products. The respective saddle points, which correspond to a collinear arrangement, are the same for both PESs, whilst the barrier height rises more abruptly on the 3A' PES than on the 3A'' PES. Accordingly, the reactivity on the 3A'' PES should be always higher than on the 3A' PES. In this work, we present accurate quantum-scattering calculations showing that this is not always the case for rotationless reactants, where dynamical factors near the reaction threshold cause the 3A' PES to dominate at energies around the barrier. Further calculation of cross sections and Λ-doublet populations has allowed us to establish how the reaction mechanism changes from the deep tunneling regime to hyperthermal energies.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37003, Salamanca, Spain
| | - A Zanchet
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37003, Salamanca, Spain and Departamento de Química Física, Facultad de Química, Universidad Complutense de Madrid (Unidad Asociada CSIC), 28040 Madrid, Spain.
| | - M Menéndez
- Departamento de Química Física, Facultad de Química, Universidad Complutense de Madrid (Unidad Asociada CSIC), 28040 Madrid, Spain.
| | - V J Herrero
- Instituto de Estructura de la Materia, IEM-CSIC c/Serrano 123, 28006 Madrid, Spain
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense de Madrid (Unidad Asociada CSIC), 28040 Madrid, Spain.
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19
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Jambrina PG, Croft JFE, Guo H, Brouard M, Balakrishnan N, Aoiz FJ. Stereodynamical Control of a Quantum Scattering Resonance in Cold Molecular Collisions. PHYSICAL REVIEW LETTERS 2019; 123:043401. [PMID: 31491255 DOI: 10.1103/physrevlett.123.043401] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Indexed: 06/10/2023]
Abstract
Cold collisions of light molecules are often dominated by a single partial wave resonance. For the rotational quenching of HD (v=1, j=2) by collisions with ground state para-H_{2}, the process is dominated by a single L=2 partial wave resonance centered around 0.1 K. Here, we show that this resonance can be switched on or off simply by appropriate alignment of the HD rotational angular momentum relative to the initial velocity vector, thereby enabling complete control of the collision outcome.
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Affiliation(s)
- Pablo G Jambrina
- Departamento de Química Física. Universidad de Salamanca, Salamanca 37008, Spain
| | - James F E Croft
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand and Department of Physics, University of Otago, Dunedin 9054, New Zealand
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Mark Brouard
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, Oxford OX1 3TA, United Kingdom
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - F Javier Aoiz
- Departamento de Química Física. Universidad Complutense. Madrid 28040, Spain
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20
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Jambrina PG, Menéndez M, Zanchet A, García E, Aoiz FJ. How reactant polarization can be used to change the effect of interference on reactive collisions. Phys Chem Chem Phys 2019; 21:14012-14022. [PMID: 30638224 DOI: 10.1039/c8cp06892e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is common knowledge that integral and differential cross sections (DCSs) are strongly dependent on the spatial distribution of the molecular axis of the reactants. Hence, by controlling the axis distribution, it is possible to either promote or hinder the yield of products into specific final states or scattering angles. This idea has been successfully implemented in experiments by polarizing the internuclear axis before the reaction takes place, either by manipulating the rotational angular distribution or by the Stark effect in the presence of an orienting field. When there is a dominant reaction mechanism, characterized by a set of impact parameters and angles of attack, it is expected that a preparation that helps the system to reach the transition state associated with that mechanism will promote the reaction, whilst a different preparation would generally impair the reaction. However, when two or more competing mechanisms via interference contribute to the reaction into specific scattering angles and final states, it is not evident which would be the effect of changing the axis preparation. To address this problem, throughout this article we have simulated the effect that different experimental preparations have on the DCSs for the H + D2 reaction at relatively high energies, for which it has been shown that several competing mechanisms give rise to interference that shapes the DCS. To this aim, we have extended the formulation of the polarization dependent DCS to calculate polarization dependent generalized deflection functions of ranks greater than zero. Our results show that interference is very sensitive to changes in the internuclear axis preparation, and that the shape of the DCS can be controlled exquisitely.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca, 37008, Spain.
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21
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Croft JFE, Balakrishnan N. Controlling rotational quenching rates in cold molecular collisions. J Chem Phys 2019; 150:164302. [PMID: 31042924 DOI: 10.1063/1.5091576] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The relative orientation and alignment of colliding molecules plays a key role in determining the rates of chemical processes. Here, we examine in detail a prototypical example: rotational quenching of HD in cold collisions with H2. We show that the rotational quenching rate from j = 2 → 0, in the v = 1 vibrational level, can be maximized by aligning the HD along the collision axis and can be minimized by aligning the HD at the so called magic angle. This follows from quite general helicity considerations and suggests that quenching rates for other similar systems can also be controlled in this manner.
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Affiliation(s)
- J F E Croft
- The Dodd Walls Centre for Photonic and Quantum Technologies, Dunedin, New Zealand
| | - N Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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22
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Affiliation(s)
- Kopin Liu
- Institution of Atomic and Molecular Sciences (IAMS), Academic Sinica, Taipei 10699
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23
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Croft JFE, Balakrishnan N, Huang M, Guo H. Unraveling the Stereodynamics of Cold Controlled HD-H_{2} Collisions. PHYSICAL REVIEW LETTERS 2018; 121:113401. [PMID: 30265091 DOI: 10.1103/physrevlett.121.113401] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Measuring inelastic rates with partial-wave resolution requires temperatures close to a Kelvin or below, even for the lightest molecule. In a recent experiment, Perreault, Mukherjee, and Zare [Nat. Chem. 10, 561 (2018).NCAHBB1755-433010.1038/s41557-018-0028-5] studied collisional relaxation of excited HD molecules in the v=1, j=2 state by para- and ortho-H_{2} at a temperature of about 1 K, extracting the angular distribution of scattered HD in the v=1, j=0 state. By state preparation of the HD molecules, control of the angular distribution of scattered HD was demonstrated. Here, we report a first-principles simulation of that experiment which enables us to attribute the main features of the observed angular distribution to a single L=2 partial-wave shape resonance. Our results demonstrate important stereodynamical insights that can be gained when numerically exact quantum scattering calculations are combined with experimental results in the few-partial-wave regime.
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Affiliation(s)
- James F E Croft
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - Meng Huang
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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24
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Sharples TR, Leng JG, Luxford TFM, McKendrick KG, Jambrina PG, Aoiz FJ, Chandler DW, Costen ML. Non-intuitive rotational reorientation in collisions of NO(A 2Σ+) with Ne from direct measurement of a four-vector correlation. Nat Chem 2018; 10:1148-1153. [DOI: 10.1038/s41557-018-0121-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 07/12/2018] [Indexed: 11/09/2022]
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25
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Pan H, Tkac O, Liu K. Rotational-mode specific effects on the stereo-requirement in the reaction of prealigned-CHD3(v1 = 1; |JK = |10 or |1 ± 1) with the chlorine atom. J Chem Phys 2018; 148:244307. [DOI: 10.1063/1.5037892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Huilin Pan
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
| | - Ondrej Tkac
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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26
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Privat E, Guillon G, Honvault P. Dependence on collision energy of the stereodynamical properties of the 18O + 32O 2 exchange reaction. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1438676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- E. Privat
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR, CNRS-Université de Bourgogne-Franche-Comté, Dijon, France
| | - G. Guillon
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR, CNRS-Université de Bourgogne-Franche-Comté, Dijon, France
| | - P. Honvault
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR, CNRS-Université de Bourgogne-Franche-Comté, Dijon, France
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27
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Jambrina PG, Menéndez M, Zanchet A, García E, Aoiz FJ. Λ-Doublet Propensities for Reactions on Competing A′ and A″ Potential Energy Surfaces: O(3P) + N2 and O(3P) + HCl. J Phys Chem A 2018; 122:2739-2750. [DOI: 10.1021/acs.jpca.7b11826] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Pablo G. Jambrina
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - M. Menéndez
- Departamento de Química Física I, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - A. Zanchet
- Departamento de Química Física I, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - E. García
- Departamento de Quimica Fisica, Universidad del Pais Vasco (UPV/EHU), 01006 Vitoria, Spain
| | - F. J. Aoiz
- Departamento de Química Física I, Universidad Complutense de Madrid, 28040, Madrid, Spain
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28
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Privat E, Guillon G, Honvault P. Quantum stereodynamics of the 18O+16O16O→16O18O+16O exchange reaction at low collision energy. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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29
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Pan H, Wang F, Czakó G, Liu K. Direct mapping of the angle-dependent barrier to reaction for Cl + CHD3 using polarized scattering data. Nat Chem 2017; 9:1175-1180. [DOI: 10.1038/nchem.2858] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/28/2017] [Indexed: 11/09/2022]
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30
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Huran AW, González-Sánchez L, Gomez-Carrasco S, Aldegunde J. A Quantum Mechanical Study of the k–j and k′–j′ Vector Correlations for the H + LiH → Li + H2 Reaction. J Phys Chem A 2017; 121:1535-1543. [DOI: 10.1021/acs.jpca.6b10094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ahmad W. Huran
- Departamento de
Química Física, Facultad de Ciencias Químicas, University of Salamanca, 37008 Salamanca, Spain
- Instituto de Ciencia Molecular, Universidad de Valencia, 46890 Paterna, Spain
| | - L. González-Sánchez
- Departamento de
Química Física, Facultad de Ciencias Químicas, University of Salamanca, 37008 Salamanca, Spain
| | - S. Gomez-Carrasco
- Departamento de
Química Física, Facultad de Ciencias Químicas, University of Salamanca, 37008 Salamanca, Spain
| | - J. Aldegunde
- Departamento de
Química Física, Facultad de Ciencias Químicas, University of Salamanca, 37008 Salamanca, Spain
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31
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Brouard M, Chadwick H, Gordon SDS, Hornung B, Nichols B, Aoiz FJ, Stolte S. Stereodynamics in NO(X) + Ar inelastic collisions. J Chem Phys 2017; 144:224301. [PMID: 27306001 DOI: 10.1063/1.4952649] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The effect of orientation of the NO(X) bond axis prior to rotationally inelastic collisions with Ar has been investigated experimentally and theoretically. A modification to conventional velocity-map imaging ion optics is described, which allows the orientation of hexapole state-selected NO(X) using a static electric field, followed by velocity map imaging of the resonantly ionized scattered products. Bond orientation resolved differential cross sections are measured experimentally for a series of spin-orbit conserving transitions and compared with quantum mechanical calculations. The agreement between experimental results and those from quantum mechanical calculations is generally good. Parity pairs, which have previously been observed in collisions of unpolarized NO with various rare gases, are not observed due to the coherent superposition of the two j = 1/2, Ω = 1/2 Λ-doublet levels in the orienting field. The normalized difference differential cross sections are found to depend predominantly on the final rotational state, and are not very sensitive to the final Λ-doublet level. The differential steric effect has also been investigated theoretically, by means of quantum mechanical and classical calculations. Classically, the differential steric effect can be understood by considering the steric requirement for different types of trajectories that contribute to different regions of the differential cross section. However, classical effects cannot account quantitatively for the differential steric asymmetry observed in NO(X) + Ar collisions, which reflects quantum interference from scattering at either end of the molecule. This quantum interference effect is dominated by the repulsive region of the potential.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - H Chadwick
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - S D S Gordon
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - B Hornung
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - B Nichols
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - S Stolte
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
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32
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Brouard M, Gordon SDS, Hackett Boyle A, Heid CG, Nichols B, Walpole V, Aoiz FJ, Stolte S. Integral steric asymmetry in the inelastic scattering of NO(X 2Π). J Chem Phys 2017; 146:014302. [PMID: 28063434 DOI: 10.1063/1.4972565] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging. Experimental integral steric asymmetries are presented for NO(X) + Ar, for both spin-orbit manifolds, and Kr, for the spin-orbit conserving manifold. The integral steric asymmetry for spin-orbit conserving and changing transitions of the NO(X) + O2 system is also presented. Close-coupled quantum mechanical scattering calculations employing well-tested ab initio potential energy surfaces were able to reproduce the steric asymmetry observed for the NO-rare gas systems. Quantum mechanical scattering and quasi-classical trajectory calculations were further used to help interpret the integral steric asymmetry for NO + O2. Whilst the main features of the integral steric asymmetry of NO with the rare gases are also observed for the O2 collision partner, some subtle differences provide insight into the form of the underlying potentials for the more complex system.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - S D S Gordon
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - A Hackett Boyle
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - C G Heid
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - B Nichols
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - V Walpole
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - S Stolte
- The Jilin Institute of Atomic and Molecular Physics, Qianjin Avenue, Changchung 130012, China
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33
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Wang F, Liu K. Differential steric effects in Cl reactions with aligned CHD3(v1 = 1) by the R(0) and Q(1) transitions. II. Abstracting the unexcited D-atoms. J Chem Phys 2016; 145:144306. [DOI: 10.1063/1.4964653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Fengyan Wang
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
- Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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34
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Wang F, Liu K. Differential steric effects in Cl reactions with aligned CHD3(v1 = 1) by the R(0) and Q(1) transitions. I. Attacking the excited C–H bond. J Chem Phys 2016; 145:144305. [DOI: 10.1063/1.4964652] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Fengyan Wang
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
- Departmemt of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
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35
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Jambrina PG, Aldegunde J, Aoiz FJ, Sneha M, Zare RN. Effects of reagent rotation on interferences in the product angular distributions of chemical reactions. Chem Sci 2016; 7:642-649. [PMID: 28791109 PMCID: PMC5523120 DOI: 10.1039/c5sc03373j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/02/2015] [Indexed: 12/26/2022] Open
Abstract
Differential cross sections (DSCs) of the HD(v', j') product for the reaction of H atoms with supersonically cooled D2 molecules in a small number of initial rotational states have been measured at a collision energy of 1.97 eV. These DCSs show an oscillatory pattern that results from interferences caused by different dynamical scattering mechanisms leading to products scattered into the same solid angle. The interferences depend on the initial rotational state j of the D2(v = 0, j) reagent and diminish in strength with increasing rotation. We present here a detailed explanation for this behavior and how each dynamical scattering mechanism has a dependence on the helicity Ω, the projection of the initial rotational angular momentum j of the D2 reagent on the approach direction. Each helicity corresponds to a different internuclear axis distribution, with the consequence that the dependence on Ω reveals the preference of the different quasiclassical mechanisms as a function of approach direction. We believe that these results are general and will appear in any reaction for which several mechanisms are operative.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física I , Facultad de Química , Universidad Complutense de Madrid , 28040 , Spain .
| | - J Aldegunde
- Departamento de Química Física , Universidad de Salamanca , Salamanca , Spain
| | - F J Aoiz
- Departamento de Química Física I , Facultad de Química , Universidad Complutense de Madrid , 28040 , Spain .
| | - M Sneha
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , USA .
| | - R N Zare
- Department of Chemistry , Stanford University , Stanford , California 94305-5080 , USA .
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36
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Aldegunde J, Jambrina PG, González-Sanchez L, Herrero VJ, Aoiz FJ. Influence of the Reactants Rotational Excitation on the H + D2(v = 0, j) Reactivity. J Phys Chem A 2015; 119:12245-54. [PMID: 26305719 PMCID: PMC4931900 DOI: 10.1021/acs.jpca.5b06286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have analyzed the influence of the rotational excitation on the H + D2(v = 0, j) reaction through quantum mechanical (QM) and quasiclassical trajectories (QCT) calculations at a wide range of total energies. The agreement between both types of calculations is excellent. We have found that the rotational excitation largely increases the reactivity at large values of the total energy. Such an increase cannot be attributed to a stereodynamical effect but to the existence of recrossing trajectories that become reactive as the target molecule gets rotationally excited. At low total energies, however, recrossing is not significant and the reactivity evolution is dominated by changes in the collision energy; the reactivity decreases with the collision energy as it shrinks the acceptance cone. When state-to-state results are considered, rotational excitation leads to cold product's rovibrational distributions, so that most of the energy is released as recoil energy.
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Affiliation(s)
- J Aldegunde
- Departamento de Química Física , Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain
| | - PG Jambrina
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - L González-Sanchez
- Departamento de Química Física , Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain
| | - VJ Herrero
- Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, 28006, Madrid, Spain
| | - FJ Aoiz
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
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37
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Brouard M, Chadwick H, Gordon SDS, Hornung B, Nichols B, Aoiz FJ, Stolte S. Rotational Orientation Effects in NO(X) + Ar Inelastic Collisions. J Phys Chem A 2015; 119:12404-16. [PMID: 26413997 DOI: 10.1021/acs.jpca.5b07846] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rotational angular momentum orientation effects in the rotationally inelastic collisions of NO(X) with Ar have been investigated both experimentally and theoretically at a collision energy of 530 cm(-1). The collision-induced orientation has been determined experimentally using a hexapole electric field to select the ϵ = -1 Λ-doublet level of the NO(X) j = 1/2 initial state. Fully quantum state resolved polarization-dependent differential cross sections were recorded experimentally using a crossed molecular beam apparatus coupled with a (1 + 1') resonance-enhanced multiphoton ionization detection scheme and subsequent velocity-map imaging. To determine the NO sense of rotation, the probe radiation was circularly polarized. Experimental orientation polarization-dependent differential cross sections are compared with those obtained from quantum mechanical scattering calculations and are found to be in good agreement. The origin of the collision-induced orientation has been investigated by means of close-coupled quantum mechanical, quantum mechanical hard shell, quasi-classical trajectory (QCT), and classical hard shell calculations at the same collision energy. Although there is evidence for the operation of limiting classical mechanisms, the rotational orientation cannot be accounted for by QCT calculations and is found to be strongly influenced by quantum mechanical effects.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - H Chadwick
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - S D S Gordon
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - B Hornung
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - B Nichols
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense , 28040 Madrid, Spain
| | - S Stolte
- Institute of Atomic and Molecular Physics, Jilin University , Changchun 130012, China.,Department of Physics and Astronomy, LaserLaB, Vrije Universiteit, Amsterdam , De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.,Laboratoire Francis Perrin, Bâtiment 522, DRECEM/SPAM/CEA Saclay, 91191 Gif sur Yvette, France
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38
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Ge MH, Yang H, Zheng Y. Theoretical study of product polarization of O(1D) + HCl(v = 0; j = 0) → ClO + H and its isotope exchange reaction. CAN J CHEM 2015. [DOI: 10.1139/cjc-2015-0288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
O(1D) + HCl(v = 0; j = 0) → ClO + H and its isotope exchange reaction O(1D) + DCl(v = 0; j = 0) → ClO + D are studied in the collision energy range 14.0–20.0 kcal/mol based on the potential energy surface 1[Formula: see text] state. Reaction probabilities, integral cross sections, the two angular distribution functions (concerning the initial/final velocity vector, and the product rotational momentum vector), and the product rotational alignment parameters are calculated as a function of the collision energy for the two reactions. The four generalized polarization dependent differential cross sections are presented to manifest the polarization characters. Also, the effect of the collision energy and the kinetic isotope effect are studied.
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Affiliation(s)
- Mei Hua Ge
- School of Physics, Shandong University, Jinan 250100, China
- School of Physics, Shandong University, Jinan 250100, China
| | - Huan Yang
- School of Physics, Shandong University, Jinan 250100, China
- School of Physics, Shandong University, Jinan 250100, China
| | - Yujun Zheng
- School of Physics, Shandong University, Jinan 250100, China
- School of Physics, Shandong University, Jinan 250100, China
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39
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Aldegunde J, González–Sánchez L, Jambrina PG, Sáez-Rábanos V, Aoiz FJ. A semiclassical treatment of the ℓ– j correlation in atom-diatom collisions. J Chem Phys 2015; 143:064302. [DOI: 10.1063/1.4928283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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40
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Ohoyama H. Atomic Alignment Effect on Reactivity and on Product Alignment in the Energy-Transfer Reaction of Oriented Ar ( 3P 2, 4s [3/2] 2, MJ = 2) + Kr (4p 6, 1S 0) → Ar (3p 6, 1S 0) + Kr (5p [3/2] 2). J Phys Chem A 2015; 119:1820-9. [DOI: 10.1021/jp509989x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- H. Ohoyama
- Department
of Chemistry,
Graduate School of Science, Osaka University Toyonaka, Osaka 560-0043, Japan
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41
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Liu K. Perspective: Vibrational-induced steric effects in bimolecular reactions. J Chem Phys 2015; 142:080901. [DOI: 10.1063/1.4913323] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
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42
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Nichols B, Chadwick H, Gordon SDS, Eyles CJ, Hornung B, Brouard M, Alexander MH, Aoiz FJ, Gijsbertsen A, Stolte S. Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar. Chem Sci 2015; 6:2202-2210. [PMID: 28694950 PMCID: PMC5485563 DOI: 10.1039/c4sc03842h] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/03/2015] [Indexed: 11/21/2022] Open
Abstract
New measurements of the differential steric effect for NO + Ar inelastic scattering highlight the importance of quantum interference.
Rotationally inelastic collisions of NO(X) with Ar are investigated in unprecedented detail using state-to-state, crossed molecular beam experiments. The NO(X) molecules are selected in the Ω = 0.5, j = 0.5, f state and then oriented such that either the ‘N’ or ‘O’ end of the molecule is directed towards the incoming Ar atom. Velocity map ion imaging is then used to probe the scattered NO molecules in well-defined quantum states. We show that the fully quantum state-resolved differential steric asymmetry, which quantifies how the relative efficiency for scattering off the ‘O’ and the ‘N’ ends of the molecule varies with scattering angle, is strongly affected by quantum interference. Significant changes in both integral and differential cross sections are found depending on whether collisions occur with the N or O ends of the molecule. The results are well accounted for by rigorous quantum mechanical calculations, in contrast to both classical trajectory calculations and more simplistic models that provide, at best, an incomplete picture of the dynamics.
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Affiliation(s)
- B Nichols
- The Department of Chemistry , University of Oxford , The Physical and Theoretical Chemistry Laboratory , South Parks Road , Oxford , OX1 3QZ , United Kingdom .
| | - H Chadwick
- The Department of Chemistry , University of Oxford , The Physical and Theoretical Chemistry Laboratory , South Parks Road , Oxford , OX1 3QZ , United Kingdom .
| | - S D S Gordon
- The Department of Chemistry , University of Oxford , The Physical and Theoretical Chemistry Laboratory , South Parks Road , Oxford , OX1 3QZ , United Kingdom .
| | - C J Eyles
- The Department of Chemistry , University of Oxford , The Physical and Theoretical Chemistry Laboratory , South Parks Road , Oxford , OX1 3QZ , United Kingdom .
| | - B Hornung
- The Department of Chemistry , University of Oxford , The Physical and Theoretical Chemistry Laboratory , South Parks Road , Oxford , OX1 3QZ , United Kingdom .
| | - M Brouard
- The Department of Chemistry , University of Oxford , The Physical and Theoretical Chemistry Laboratory , South Parks Road , Oxford , OX1 3QZ , United Kingdom .
| | - M H Alexander
- Department of Chemistry and Biochemistry and Institute of Physical Science and Technology , University of Maryland , College Park , MD 20742 , USA .
| | - F J Aoiz
- Departamento de Química Física , Facultad de Química , Universidad Complutense , 28040 Madrid , Spain .
| | - A Gijsbertsen
- Institute for Lasers, Life and Biophotonics , Vrije Universiteit , de Boelelaan 1083 , Amsterdam 1081 HV , The Netherlands
| | - S Stolte
- Institute of Atomic and Molecular Physics , Jilin University , Changchun 130012 , China . .,Department of Physics and Astronomy , LaserLaB , Vrije Universiteit , de Boelelaan 1083 , Amsterdam 1081 HV , The Netherlands.,Laboratoire Francis Perrin , Bâtiment 522, DRECEM/SPAM/CEA Saclay , 91191 Gif sur Yvette , France
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43
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Eyles CJ, Floß J, Averbukh IS, Leibscher M. Atom-diatom scattering dynamics of spinning molecules. J Chem Phys 2015; 142:024311. [DOI: 10.1063/1.4905251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C. J. Eyles
- Institut für Chemie und Biochemie, Freie Universität Berlin, 14195 Berlin, Germany
| | - J. Floß
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - I. Sh. Averbukh
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - M. Leibscher
- Institut für Theoretische Physik, Leibniz Universität Hannover, 30167 Hannover, Germany
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44
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Aoiz FJ, Brouard M, Gordon SDS, Nichols B, Stolte S, Walpole V. A new perspective: imaging the stereochemistry of molecular collisions. Phys Chem Chem Phys 2015; 17:30210-28. [DOI: 10.1039/c5cp03273c] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The concept of the steric effect plays a central role in chemistry. This Perspective describes how the polarization of reactant molecules in space can be used to probe directly the steric effect, and highlights some of the new measurements that are made possible by coupling reactant orientation and alignment with ion imaging techniques.
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Affiliation(s)
- F. J. Aoiz
- Departamento de Química Física
- Facultad de Química
- Universidad Complutense
- 28040 Madrid
- Spain
| | - M. Brouard
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
| | - S. D. S. Gordon
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
| | - B. Nichols
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
| | - S. Stolte
- Institute of Atomic and Molecular Physics
- Jilin University
- Changchun 130012
- China
- Department of Physics and Astronomy
| | - V. Walpole
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
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45
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Pan H, Yang J, Wang F, Liu K. Imaging the Stereodynamics of Cl + CH4(ν3 = 1): Polarization Dependence on the Rotational Branch and the Hyperfine Depolarization. J Phys Chem Lett 2014; 5:3878-3883. [PMID: 26278763 DOI: 10.1021/jz502088c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The transition state in the Cl + CH4 reaction is of Cl-H-C collinear geometry, which serves as the bottleneck to reaction. When the reactant CH4 is antisymmetrically stretch-excited to ν3 = 1 by absorbing a linearly polarized photon, all four C-H bonds are collectively excited, and any one of the H atoms could be attacked by the Cl atom. At first sight, it is not obvious how an excited spherical-top molecule like CH4 is aligned and what consequences will be on chemical reactivity by polarizing the CH4 reagents. As shown here, an enormous steric effect on reactivity is observed, which depends sensitively on the selected rotational states. By exploiting various rotational branches in optical excitation, we quantify the degree of stereospecificity for a few lowest rovibrational states of the aligned CH4(ν3 = 1) reagents, as well as account for the hyperfine depolarization factor. This information lays the foundation for a full stereorequirement study of the Cl + CH4(ν3 = 1) reaction.
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Affiliation(s)
- Huilin Pan
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Jiayue Yang
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Fengyan Wang
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Kopin Liu
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
- ‡Department of Physics, National Taiwan University, Taipei, Taiwan 10617
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46
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Brouard M, Chadwick H, Gordon SDS, Hornung B, Nichols B, Kłos J, Aoiz FJ, Stolte S. Fully quantum state-resolved inelastic scattering of NO(X) + Kr: Differential cross sections and product rotational alignment. J Chem Phys 2014; 141:164306. [DOI: 10.1063/1.4897558] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- M. Brouard
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - H. Chadwick
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - S. D. S. Gordon
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - B. Hornung
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - B. Nichols
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - J. Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - F. J. Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - S. Stolte
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
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47
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Wang F, Lin JS, Liu K. How to measure a complete set of polarization-dependent differential cross sections in a scattering experiment with aligned reagents? J Chem Phys 2014; 140:084202. [DOI: 10.1063/1.4865673] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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48
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49
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Ge M, Yang H, Zheng Y. The dynamical study of O(1D) + HCl(v = 0, j = 0) reaction at hyperthermal collision energies. Chem Cent J 2013; 7:177. [PMID: 24237765 PMCID: PMC4176982 DOI: 10.1186/1752-153x-7-177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 11/07/2013] [Indexed: 11/21/2022] Open
Abstract
Backgrounds The quasi-classical trajectory calculations for O(1D) + HCl → OH + Cl (R1) and O(1D) + HCl → ClO + H (R2) reactions have been performed at hyperthermal collision energies (60.0, 90.0, and 120.0 kal/mol) on the 1A' state. Reaction probabilities and integral cross sections are calculated. The product rotational distributions for the two channels, and the product rotational alignment parameters are investigated. Also, the alignment and the orientation of the products have been predicted through the angular distribution functions (concerning the initial/final velocity vector, and the product rotational angular momentum vector). To have a deeper understanding of the natures of the vector correlation between reagent and product relative velocities, a natural generalization of the differential cross section __PDDCS00, is calculated. Results The OH + Cl channel is the main product channel and is observed to have essentially isotropic rotational distributions. The ClO + H channel is found to be clearly rotationally polarized. Conclusions The dynamical, especially the stereodynamical characters are quite different for the two channels of the title reaction. Most reactions occur directly, except for R2 reaction at the collision energies of 60.0 and 120.0 kcal/mol. The alignment and orientation effects are weak/strong for R1/R2 reaction. The well structure on the potential energy surface and hyperthermal collision energies might result in the dynamical effects.
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Affiliation(s)
- Meihua Ge
- School of Physics, Shandong University, Jinan 250100, China.
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50
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Herráez-Aguilar D, Jambrina PG, Aldegunde J, Sáez-Rábanos V, de Miranda MP, Aoiz FJ. The reactive collision mechanism evinced: stereodynamical control of the elementary Br + H2 → H + HBr reaction. Phys Chem Chem Phys 2013; 15:13513-22. [PMID: 23823942 DOI: 10.1039/c3cp51271a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
From a kinetics standpoint, reactive molecular collisions are the building blocks of the mechanisms of chemical reactions. In contrast, a dynamics standpoint reveals molecular collisions to have their own internal mechanisms, which are not mere theoretical abstractions: through suitable preparation of the reactants internal and stereochemical states, features of the mechanisms of a reactive molecular collision can be made evident and used as "handles" to control the reaction outcome. Using time-independent quantum dynamical calculations, we demonstrate this for the Br + H2(v = 0-1, j = 2) → H + HBr reaction in the 1.0-1.6 eV range of total energies. Despite its pronounced effect on reactivity, which is in agreement with the predictions from Polanyi rules, reactant vibration is found to have little effect on the mechanism of this endoergic, late-barrier reaction. Analysis of the correlations between directional reaction properties shows that the collision stereochemistry strongly depends on the total energy, but not on how this energy is partitioned between reactant translation and vibration. The stereodynamical preferences implied by the collision mechanisms determine how and to what extent one can control the reaction. Regarding the overall reaction, the extent of control is found to be large near the reaction threshold but not when the total energy is high. Regarding state-to-state reactions, the effect of reactant stereochemistry on the product rotational state distribution is found to be nontrivial and energy dependent.
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Affiliation(s)
- D Herráez-Aguilar
- Departamento de Quimica Fisica I, Facultad de Quimica, Universidad Complutense de Madrid, 28040, Spain
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