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Benitez Y, Nguyen TL, Parsons AJ, Stanton JF, Continetti RE. Probing the Exit Channel of the OH + CH 3OH → H 2O + CH 3O Reaction by Photodetachment of CH 3O -(H 2O). J Phys Chem Lett 2022; 13:142-148. [PMID: 34962408 DOI: 10.1021/acs.jpclett.1c03568] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transition state dynamics of bimolecular reactions can be probed by photodetachment of a precursor anion when the Franck-Condon region of the corresponding neutral potential energy surface is near a saddle point. In this study, photodetachment of anions at m/z = 49 enabled investigation of the exit channel of the OH + CH3OH → H2O + CH3O reaction using photoelectron-photofragment coincidence spectroscopy. High-level coupled-cluster calculations of the stationary points on the anion surface show that the methoxide-water cluster CH3O-(H2O) is the stable minimum on the anion surface. Photodetachment at a 3.20 eV photon energy leads to long-lived H2O(CH3O) complexes and H2O + CH3O products consistent with both direct dissociative photodetachment and resonance mediated processes on the neutral surface. The partitioning of total kinetic energy in the system indicates that water stretch and bend excitation is induced in dissociative photodetachment and evidence for long-lived complexes consistent with vibrational Feshbach resonances is reported.
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Affiliation(s)
- Yanice Benitez
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Thanh Lam Nguyen
- Quantum Theory Project, Department of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Austin J Parsons
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - John F Stanton
- Quantum Theory Project, Department of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Robert E Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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2
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Product Vibrational State Distributions of the F CH 3OH Reaction on a Full-Dimensional Accurate Potential Energy Surface. CHINESE J CHEM PHYS 2022. [DOI: 10.1063/1674-0068/cjcp2111252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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3
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Benitez Y, Parsons AJ, Lunny KG, Continetti RE. Dissociative Photodetachment Dynamics of the OH -(C 2H 4) Anion Complex. J Phys Chem A 2021; 125:4540-4547. [PMID: 34030440 DOI: 10.1021/acs.jpca.1c01835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoelectron-photofragment coincidence (PPC) measurements on OH-(C2H4) anions at a photon energy of 3.20 eV revealed stable and dissociative photodetachment product channels, OH-C2H4 + e- and OH + C2H4 + e-, respectively. The main product channel observed was dissociation to the reactants (>67%), OH + C2H4 (v = 0, 1, 2) + e-, where vibrational excitation in the C-H stretching modes of the C2H4 photofragments corresponds to a minor channel. The low kinetic energy release (KER) of the dissociating fragments is consistent with weak repulsion between the OH + C2H4 reactants near the transition state as well as the partitioning of energy into rotation of the dissociation products. An impulsive model was used to account for rotational energy partitioning in the dissociative photodetachment (DPD) process and showed good agreement with the experimental results. The low KER of the dissociating fragments and the similarities in the photoelectron spectra between stable and dissociative events support a mechanism involving the van der Waals complex formed upon photodetachment of OH-(C2H4) as an intermediate in the dominant OH + C2H4 + e- dissociative channel.
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Affiliation(s)
- Yanice Benitez
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Austin J Parsons
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Katharine G Lunny
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Robert E Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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Szűcs T, Czakó G. Benchmark ab initio stationary-point characterization of the complex potential energy surface of the multi-channel Cl + CH 3NH 2 reaction. Phys Chem Chem Phys 2021; 23:10347-10356. [PMID: 33881412 DOI: 10.1039/d0cp06392d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We characterize the exothermic low/submerged-barrier hydrogen-abstraction (HCl + CH2NH2/CH3NH) as well as, for the first time, the endothermic high-barrier amino-substitution (CH3Cl + NH2), methyl-substitution (NH2Cl + CH3), and hydrogen-substitution (CH2ClNH2/CH3NHCl + H) pathways of the Cl + CH3NH2 reaction using an accurate composite ab initio approach. The computations reveal a CH3NH2Cl complex in the entrance channel, nine transition states corresponding to different abstractions, Walden-inversion substitution, and configuration-retaining front-side attack substitution pathways, as well as nine post-reaction complexes. The global minima of the electronic and vibrationally adiabatic potential energy surfaces correspond to the pre-reaction CH3NH2Cl and post-reaction CH2NH2HCl complexes, respectively. The benchmark composite energies of the stationary points are obtained by considering basis-set effects up to the correlation-consistent polarized valence quadruple-zeta basis augmented with diffuse functions (aug-cc-pVQZ) using the explicitly-correlated coupled-cluster singles, doubles, and perturbative triples CCSD(T)-F12b method, post-(T) correlation up to CCSDT(Q) including full triples and perturbative quadruples, core correlation, and scalar relativistic and spin-orbit effects, as well as harmonic zero-point energy corrections.
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Affiliation(s)
- Tímea Szűcs
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
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Li J, Zhao B, Xie D, Guo H. Advances and New Challenges to Bimolecular Reaction Dynamics Theory. J Phys Chem Lett 2020; 11:8844-8860. [PMID: 32970441 DOI: 10.1021/acs.jpclett.0c02501] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dynamics of bimolecular reactions in the gas phase are of foundational importance in combustion, atmospheric chemistry, interstellar chemistry, and plasma chemistry. These collision-induced chemical transformations are a sensitive probe of the underlying potential energy surface(s). Despite tremendous progress in past decades, our understanding is still not complete. In this Perspective, we survey the recent advances in theoretical characterization of bimolecular reaction dynamics, stimulated by new experimental observations, and identify key new challenges.
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Affiliation(s)
- Jun Li
- School of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
| | - Bin Zhao
- Theoretische Chemie, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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Lu D, Li J, Guo H. Stereodynamical control of product branching in multi-channel barrierless hydrogen abstraction of CH 3OH by F. Chem Sci 2019; 10:7994-8001. [PMID: 31853354 PMCID: PMC6836967 DOI: 10.1039/c9sc02445j] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/08/2019] [Indexed: 11/21/2022] Open
Abstract
Comprehensive dynamical simulations of a prototypical multi-channel reaction on a globally accurate potential energy surface show that the non-statistical product branching is dictated by unique stereodynamics in the entrance channels.
Hydrogen abstraction from methanol (CH3OH) by F atoms presents an ideal proving ground to investigate dynamics of multi-channel reactions, because two types of hydrogen can be abstracted from the methanol molecule leading to the HF + CH3O and HF + CH2OH products. Using the quasi-classical trajectory approach on a globally accurate potential energy surface based on high-level ab initio calculations, this work reports a comprehensive dynamical investigation of this multi-channel reaction, yielding measurable attributes including integral and differential cross sections, as well as branching ratios. It is shown that while complex-forming and direct mechanisms coexist at low collision energies, these barrierless reaction channels are dominated at high energies by the direct mechanism, in which the reaction is only possible for trajectories entering into the respective dynamical cones of acceptance. Perhaps more importantly, the non-statistical product branching is found to be dictated by unique stereodynamics in the entrance channels.
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Affiliation(s)
- Dandan Lu
- School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 401331 , China .
| | - Jun Li
- School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 401331 , China .
| | - Hua Guo
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , USA .
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Lu DD, Xie CJ, Li J, Guo H. Rate coefficients and branching ratio for multi-channel hydrogen abstractions from CH3OH by F. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1811256] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Dan-dan Lu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331,
China
| | - Chang-jian Xie
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131,
USA
| | - Jun Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331,
China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131,
USA
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Guo L, Li J, Ma J, Guo H. Quantum dynamical investigation of product state distributions of the F + CH3OH → HF + CH3O reaction via photodetachment of the F−(HOCH3) anion. J Chem Phys 2019; 150:044301. [DOI: 10.1063/1.5082274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Lifen Guo
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, China
| | - Jun Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China
| | - Jianyi Ma
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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Abstract
Slow photoelectron velocity-map imaging spectroscopy of cryogenically cooled anions (cryo-SEVI) is a powerful technique for elucidating the vibrational and electronic structure of neutral radicals, clusters, and reaction transition states. SEVI is a high-resolution variant of anion photoelectron spectroscopy based on photoelectron imaging that yields spectra with energy resolution as high as 1-2 cm-1. The preparation of cryogenically cold anions largely eliminates hot bands and dramatically narrows the rotational envelopes of spectral features, enabling the acquisition of well-resolved photoelectron spectra for complex and spectroscopically challenging species. We review the basis and history of the SEVI method, including recent experimental developments that have improved its resolution and versatility. We then survey recent SEVI studies to demonstrate the utility of this technique in the spectroscopy of aromatic radicals, metal and metal oxide clusters, nonadiabatic interactions between excited states of small molecules, and transition states of benchmark bimolecular reactions.
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Affiliation(s)
- Marissa L Weichman
- Department of Chemistry, University of California, Berkeley, California 94720, USA; , .,Current affiliation: JILA, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA; , .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Wang T, Yang T, Xiao C, Sun Z, Zhang D, Yang X, Weichman ML, Neumark DM. Dynamical resonances in chemical reactions. Chem Soc Rev 2018; 47:6744-6763. [DOI: 10.1039/c8cs00041g] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transition state is a key concept in the field of chemistry and is important in the study of chemical kinetics and reaction dynamics.
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Affiliation(s)
- Tao Wang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Tiangang Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Donghui Zhang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | | | - Daniel M. Neumark
- Department of Chemistry
- University of California at Berkeley
- Berkeley
- USA
- Chemical Sciences Division
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12
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Ray AW, Ma J, Otto R, Li J, Guo H, Continetti RE. Effects of vibrational excitation on the F + H 2O → HF + OH reaction: dissociative photodetachment of overtone-excited [F-H-OH] . Chem Sci 2017; 8:7821-7833. [PMID: 29163919 PMCID: PMC5674243 DOI: 10.1039/c7sc03364h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/23/2017] [Indexed: 11/21/2022] Open
Abstract
Photodetaching vibrationally excited FH2O– channels energy into the reaction coordinate of the F + H2O reaction, as shown in this joint experimental-theoretical study.
The reaction F + H2O → HF + OH is a four-atom system that provides an important benchmark for reaction dynamics. Hydrogen atom transfer at the transition state for this reaction is expected to exhibit a strong dependence on reactant vibrational excitation. In the present study, the vibrational effects are examined by photodetachment of vibrationally excited F–(H2O) precursor anions using photoelectron-photofragment coincidence (PPC) spectroscopy and compared with full six-dimensional quantum dynamical calculations on ab initio potential energy surfaces. Prior to photodetachment at hνUV = 4.80 eV, the overtone of the ionic hydrogen bond mode in the precursor F–(H2O), 2νIHB at 2885 cm–1, was excited using a tunable IR laser. Experiment and theory show that vibrational energy in the anion can be effectively carried away by the photoelectron upon a Franck–Condon photodetachment, and also show evidence for an increase of branching into the F + H2O reactant channel. The experimental results suggest a greater role for product rotational excitation than theory. Improved potential energy surfaces and longer wavepacket propagation times would be helpful to further examine the nature of the discrepancy.
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Affiliation(s)
- Amelia W Ray
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0340 , USA .
| | - Jianyi Ma
- Institute of Atomic and Molecular Physics , Sichuan University , Chengdu , Sichuan 610065 , China .
| | - Rico Otto
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0340 , USA .
| | - Jun Li
- School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 401331 , China
| | - Hua Guo
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , USA
| | - Robert E Continetti
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0340 , USA .
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Hou GL, Wang XB, McCoy AB, Borden WT. Experimental and Theoretical Studies of the F• + H–F Transition-State Region by Photodetachment of [F–H–F]−. J Phys Chem A 2017; 121:7895-7902. [DOI: 10.1021/acs.jpca.7b07682] [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)
- Gao-Lei Hou
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Xue-Bin Wang
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Anne B. McCoy
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Weston Thatcher Borden
- Department
of Chemistry and the Center for Advanced Scientific Computing and
Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
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Weichman ML, DeVine JA, Babin MC, Li J, Guo L, Ma J, Guo H, Neumark DM. Feshbach resonances in the exit channel of the F + CH3OH → HF + CH3O reaction observed using transition-state spectroscopy. Nat Chem 2017; 9:950-955. [DOI: 10.1038/nchem.2804] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/19/2017] [Indexed: 11/09/2022]
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15
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Abstract
Recent experimental and theoretical advances in transient reaction dynamics probed by photodetachment of polyatomic anions are reviewed.
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Affiliation(s)
- Robert E. Continetti
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
| | - Hua Guo
- Department of Chemistry and Chemical Biology
- University of New Mexico
- Albuquerque
- USA
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