51
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Nguyen TL, Stanton JF. Pragmatic Solution for a Fully E,J-Resolved Master Equation. J Phys Chem A 2020; 124:2907-2918. [DOI: 10.1021/acs.jpca.9b11379] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thanh Lam Nguyen
- Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - John F. Stanton
- Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
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52
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Barber VP, Hansen AS, Georgievskii Y, Klippenstein SJ, Lester MI. Experimental and theoretical studies of the doubly substituted methyl-ethyl Criegee intermediate: Infrared action spectroscopy and unimolecular decay to OH radical products. J Chem Phys 2020; 152:094301. [PMID: 33480748 DOI: 10.1063/5.0002422] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The infrared (IR) action spectrum of the doubly substituted methyl-ethyl Criegee intermediate (MECI) is observed in the CH stretch overtone region with detection of OH products. The MECI exhibits four conformers, all of which undergo unimolecular decay via a 1,4 H-atom transfer mechanism, followed by the rapid release of OH products. Conformers with different orientations of the carbonyl oxide group with respect to the methyl and ethyl substituents (i.e., anti and syn) decay via distinct transition state barriers (16.1 kcal mol-1 and 15.4 kcal mol-1, respectively). The observed IR action spectrum is in good agreement with the predicted anharmonic IR absorption spectrum, but exhibits significant congestion, which is attributed to couplings between spectroscopic bright states and nearby dark states. Energy-dependent OH appearance rates are measured upon IR excitation of the strongest features in the IR action spectrum and are found to be on the order of 106-107 s-1. The experimental rates are in good agreement with computed Rice-Ramsperger-Kassel-Marcus rates for the unimolecular decay of MECI at these energies, which incorporate quantum mechanical tunneling and sophisticated hindered rotor treatments, as well as high-level theoretical calculations of the TS barrier heights, rovibrational properties, and torsional barriers associated with the MECI conformers. Master equation modeling is used to predict thermal rates for the unimolecular decay of anti- and syn-MECI of 473 s-1 and 660 s-1, respectively. Comparison with other previously studied Criegee intermediate systems provides insights into substituent effects on unimolecular decay under both energy-dependent and thermal conditions.
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Affiliation(s)
- Victoria P Barber
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Anne S Hansen
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yuri Georgievskii
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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53
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The role of ammonia and amines in the isomerization of Criegee intermediates: A theoretical study. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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54
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Smith CD, Karton A. Kinetics and Thermodynamics of Reactions Involving Criegee Intermediates: An Assessment of Density Functional Theory and Ab Initio Methods Through Comparison with CCSDT(Q)/CBS Data. J Comput Chem 2020; 41:328-339. [PMID: 31750964 DOI: 10.1002/jcc.26106] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 12/21/2022]
Abstract
Reactions involving Criegee intermediates (CIs, R1 R2 COO) are important in atmospheric ozonolysis models. In recent years, density functional theory (DFT) and CCSD(T)-based ab initio methods are increasingly being used for modeling reaction profiles involving CIs. We obtain highly accurate CCSDT(Q)/CBS reaction energies and barrier heights for ring-closing reactions involving atmospherically important CIs (R1 /R2 = H, Me, OH, OMe, F, CN, cyclopropene, ethylene, acetaldehyde, and acrolein). We use this benchmark data to evaluate the performance of DFT, double-hybrid DFT (DHDFT), and ab initio methods for the kinetics and thermodynamics of these reactions. We find that reaction energies are more challenging for approximate theoretical procedures than barrier heights. Overall, taking both reaction energies and barrier heights into account, only one of the 58 considered DFT methods (the meta-GGA MN12-L) attains near chemical accuracy, with root-mean-square deviations (RMSDs) of 3.5 (barrier heights) and 4.7 (reaction energies) kJ mol-1 . Therefore, MN12-L is recommended for investigations where CCSD(T)-based methods are not computationally feasible. For reaction barrier heights performance does not strictly follow Jacob's Ladder, for example, DHDFT methods do not perform better than conventional DFT methods. Of the ab initio methods, the cost-effective CCSD(T)/CBS(MP2) approach gives the best performance for both reaction energies and barrier heights, with RMSDs of 1.7 and 1.4 kJ mol-1 , respectively. All the considered Gaussian-n methods show good performance with RMSDs below the threshold of chemical accuracy for both reaction energies and barrier heights, where G4(MP2) shows the best overall performance with RMSDs of 2.9 and 1.5 kJ mol-1 , respectively. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Cameron D Smith
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
| | - Amir Karton
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, 6009, Australia
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55
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Tan XF, Zhang L, Long B. New mechanistic pathways for the formation of organosulfates catalyzed by ammonia and carbinolamine formation catalyzed by sulfuric acid in the atmosphere. Phys Chem Chem Phys 2020; 22:8800-8807. [DOI: 10.1039/c9cp06297a] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfuric acid exerts a remarkable catalytic role in the H2SO4 + HCHO + NH3 reaction that leads to the formation of carbinolamine.
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Affiliation(s)
- Xing-Feng Tan
- School of Mechatronics Engineering
- Guizhou Minzu University
- Guiyang
- China
| | - Lin Zhang
- Department of Physics
- Guizhou University
- Guiyang
- China
| | - Bo Long
- School of Materials Science and Engineering, Guizhou Minzu University
- Guiyang
- China
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56
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Domingo LR, Seif A, Mazarei E, Zahedi E, Ahmadi TS. A molecular electron density theory (MEDT) study of the role of halogens (X 2 = F 2, Cl 2, Br 2 and I 2) on the aza-Michael-addition reactions. NEW J CHEM 2020. [DOI: 10.1039/d0nj04203j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The energy profile for gas phase F2-catalyzed nucleophilic attack of PYR R1 on the β-conjugated carbon of MA R2 marked.
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Affiliation(s)
- Luis R. Domingo
- Department of Organic Chemistry
- University of Valencia
- 46100 Burjassot
- Spain
| | - Ahmad Seif
- Department of Organic Chemistry
- University of Valencia
- 46100 Burjassot
- Spain
- Department of Chemistry
| | - Elham Mazarei
- Department of Organic Chemistry
- University of Valencia
- 46100 Burjassot
- Spain
| | - Ehasn Zahedi
- Department of Chemistry
- Shahrood Branch
- Islamic Azad University
- Shahrood
- Iran
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57
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Stephenson TA, Lester MI. Unimolecular decay dynamics of Criegee intermediates: Energy-resolved rates, thermal rates, and their atmospheric impact. INT REV PHYS CHEM 2019. [DOI: 10.1080/0144235x.2020.1688530] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Thomas A. Stephenson
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA, USA
| | - Marsha I. Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
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58
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Zhang T, Wen M, Zhang Y, Lan X, Long B, Wang R, Yu X, Zhao C, Wang W. Atmospheric chemistry of the self-reaction of HO 2 radicals: stepwise mechanism versus one-step process in the presence of (H 2O) n (n = 1-3) clusters. Phys Chem Chem Phys 2019; 21:24042-24053. [PMID: 31646308 DOI: 10.1039/c9cp03530c] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of water on radical-radical reactions are of great importance for the elucidation of the atmospheric oxidation process of free radicals. In the present work, the HO2 + HO2 reactions with (H2O)n (n = 1-3) have been investigated using quantum chemical methods and canonical variational transition state theory with small curvature tunneling. We have explored both one-step and stepwise mechanisms, in particular the stepwise mechanism initiated by ring enlargement. The calculated results have revealed that the stepwise mechanism is the dominant one in the HO2 + HO2 reaction that is catalyzed by one water molecule. This is because its pseudo-first-order rate constant (kRWM1') is 3 orders of magnitude larger than that of the corresponding one-step mechanism. Additionally, the value of kRWM1' at 298 K has been found to be 4.3 times larger than that of the rate constant of the HO2 + HO2 reaction (kR1) without catalysts, which is in good agreement with the experimental findings. The calculated results also showed that the stepwise mechanism is still dominant in the (H2O)2 catalyzed reaction due to its higher pseudo-first-order rate constant, which is 3 orders of magnitude larger than that of the corresponding one-step mechanism. On the other hand, the one-step process is much faster than the stepwise mechanism by a factor of 105-106 in the (H2O)3 catalyzed reaction. However, the pseudo-first-order rate constants for the (H2O)2 and (H2O)3-catalyzed reactions are lower than that of the H2O-catalyzed reaction by 3-4 orders of magnitude, which indicates that the water monomer is the most efficient one among all the catalysts of (H2O)n (n = 1-3). The present results have provided a definitive example that water and water clusters have important influences on atmospheric reactions.
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Affiliation(s)
- Tianlei Zhang
- Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Science, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, P. R. China.
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59
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Karton A. Highly Accurate CCSDT(Q)/CBS Reaction Barrier Heights for a Diverse Set of Transition Structures: Basis Set Convergence and Cost-Effective Approaches for Estimating Post-CCSD(T) Contributions. J Phys Chem A 2019; 123:6720-6732. [DOI: 10.1021/acs.jpca.9b04611] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Amir Karton
- School of Molecular Sciences, The University of Western Australia, Perth, WA 6009, Australia
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60
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Zhang T, Zhang Y, Wen M, Tang Z, Long B, Yu X, Zhao C, Wang W. Effects of water, ammonia and formic acid on HO 2 + Cl reactions under atmospheric conditions: competition between a stepwise route and one elementary step. RSC Adv 2019; 9:21544-21556. [PMID: 35521297 PMCID: PMC9066192 DOI: 10.1039/c9ra03541a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 07/29/2019] [Accepted: 06/27/2019] [Indexed: 11/22/2022] Open
Abstract
Quantum chemical calculations at M06-2X and CCSD(T) levels of theory have been performed to investigate the effects of H2O, NH3, and HCOOH on the HO2 + Cl → HCl + O2 reaction. The results show that catalyzed reactions with three catalysts could proceed through two different mechanisms, namely a stepwise route and one elementary step, where the former reaction is more favorable than the latter. Meanwhile, for the stepwise route, a single hydrogen atom transfer pathway in the presence of all catalysts has more advantages than the respective double hydrogen atom transfer pathway. Then, the relative impacts of catalysts under tropospheric conditions were investigated by considering the temperature dependence of the rate constants and the altitude dependence of catalyst concentrations. The calculated results show that at 0 km altitude, the HO2 + Cl → HCl + O2 reaction with catalysts, such as H2O, NH3, or HCOOH, cannot compete with the reaction without a catalyst, as the effective rate constant with a catalyst is smaller by 2–6 orders of magnitude than the naked reaction within the temperature range 280–320 K. The calculated results also show that at altitudes of 5, 10 and 15 km, the effective rate constant of the HCOOH-catalyzed reaction increases obviously with an increase in altitude. At 15 km altitude, its value is up to 9.63 × 10−11 cm3 per molecule per s, which is close to the corresponding value of the reaction without a catalyst, showing that the contribution of HCOOH to the HO2 + Cl → HCl + O2 reaction cannot be neglected at high altitudes. The new findings in this investigation are not only of great necessity and importance for elucidating the gas-phase reaction of HO2 with Cl in the presence of acidic, neutral and basic catalysts, but are also of great interest for understanding the importance of other types of hydrogen abstraction in the atmosphere. The effects of acidic (FA), neutral (WM) and basic (AM) catalysts on the energetic and kinetic aspects of the HO2 + Cl reaction have been studied. At 298 K, the catalytic order of FA, WM and AM is WM > FA > AM.![]()
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Affiliation(s)
- Tianlei Zhang
- Shaanxi Key Laboratory of Catalysis
- School of Chemical & Environment Science
- Shaanxi University of Technology
- Hanzhong
- P. R. China
| | - Yongqi Zhang
- Shaanxi Key Laboratory of Catalysis
- School of Chemical & Environment Science
- Shaanxi University of Technology
- Hanzhong
- P. R. China
| | - Mingjie Wen
- Shaanxi Key Laboratory of Catalysis
- School of Chemical & Environment Science
- Shaanxi University of Technology
- Hanzhong
- P. R. China
| | - Zhuo Tang
- Shaanxi Key Laboratory of Catalysis
- School of Chemical & Environment Science
- Shaanxi University of Technology
- Hanzhong
- P. R. China
| | - Bo Long
- School of Materials Science and Engineering
- Guizhou Minzu University
- Guiyang 550025
- P. R. China
| | - Xiaohu Yu
- Shaanxi Key Laboratory of Catalysis
- School of Chemical & Environment Science
- Shaanxi University of Technology
- Hanzhong
- P. R. China
| | - Caibin Zhao
- Shaanxi Key Laboratory of Catalysis
- School of Chemical & Environment Science
- Shaanxi University of Technology
- Hanzhong
- P. R. China
| | - Wenliang Wang
- Key Laboratory for Macromolecular Science of Shaanxi Province
- School of Chemistry & Chemical Engineering
- Shaanxi Normal University
- Xi'an
- P. R. China
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