1
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Nguyen TN, Nguyen HMT. Prediction of the product channels in the reaction of the methyl radical with fulminic acid. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Trong Nghia Nguyen
- School of Chemical Engineering, Hanoi University of Science and Technology Hanoi Vietnam
| | - Hue Minh Thi Nguyen
- Faculty of Chemistry and Center for Computational Science Hanoi National University of Education Hanoi Vietnam
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2
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Nguyen HMT, Pham TV, Van Hoang H, Hoan PT, Cuong NT. Mechanism and kinetics of the reaction of the 2‐propargyl radical with ammonia. INT J CHEM KINET 2019. [DOI: 10.1002/kin.21332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hue Minh Thi Nguyen
- Faculty of Chemistry and Center for Computational ScienceHanoi National University of Education Hanoi Vietnam
| | - Tien Van Pham
- School of Chemical EngineeringHanoi University of Science and Technology Hanoi Vietnam
| | - Hung Van Hoang
- Faculty of Chemistry and Center for Computational ScienceHanoi National University of Education Hanoi Vietnam
| | - Pham Tho Hoan
- Faculty of Information Technology and Center for Computational ScienceHanoi National University of Education Hanoi Vietnam
| | - Ngo Tuan Cuong
- Faculty of Chemistry and Center for Computational ScienceHanoi National University of Education Hanoi Vietnam
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3
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Abstract
Abstract
Remarkable progress has occurred over the last 100 years in our understanding of atmospheric chemical composition, stratospheric and tropospheric chemistry, urban air pollution, acid rain, and the formation of airborne particles from gas-phase chemistry. Much of this progress was associated with the developing understanding of the formation and role of ozone and of the oxides of nitrogen, NO and NO2, in the stratosphere and troposphere. The chemistry of the stratosphere, emerging from the pioneering work of Chapman in 1931, was followed by the discovery of catalytic ozone cycles, ozone destruction by chlorofluorocarbons, and the polar ozone holes, work honored by the 1995 Nobel Prize in Chemistry awarded to Crutzen, Rowland, and Molina. Foundations for the modern understanding of tropospheric chemistry were laid in the 1950s and 1960s, stimulated by the eye-stinging smog in Los Angeles. The importance of the hydroxyl (OH) radical and its relationship to the oxides of nitrogen (NO and NO2) emerged. The chemical processes leading to acid rain were elucidated. The atmosphere contains an immense number of gas-phase organic compounds, a result of emissions from plants and animals, natural and anthropogenic combustion processes, emissions from oceans, and from the atmospheric oxidation of organics emitted into the atmosphere. Organic atmospheric particulate matter arises largely as gas-phase organic compounds undergo oxidation to yield low-volatility products that condense into the particle phase. A hundred years ago, quantitative theories of chemical reaction rates were nonexistent. Today, comprehensive computer codes are available for performing detailed calculations of chemical reaction rates and mechanisms for atmospheric reactions. Understanding the future role of atmospheric chemistry in climate change and, in turn, the impact of climate change on atmospheric chemistry, will be critical to developing effective policies to protect the planet.
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4
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Experiments on collisional energy transfer. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/b978-0-444-64207-3.00001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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5
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Dharmarathne NK, Mackie JC, Kennedy EM, Stockenhuber M. Mechanism and Rate of Thermal Decomposition of Hexachlorocyclopentadiene and Its Importance in PCDD/F Formation from the Combustion of Cyclodiene Pesticides. J Phys Chem A 2017; 121:5871-5883. [PMID: 28682607 DOI: 10.1021/acs.jpca.7b05209] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Thermal decomposition of hexachlorocyclopentadiene (HCCP) has been studied in inert gas and under oxidative conditions in a silica flow reactor at a residence time of 5.0 s between 690 and 923 K and 1 atm pressure. Pyrolysis was initiated by Cl bond fission to form pentachlorocyclopentadienyl radical; two such radicals then combined to undergo a series of intramolecular rearrangements and Cl fissions, producing principally octachloronaphthalene (8ClNP) and Cl2. This process has been studied by quantum chemical calculation, and a reaction potential energy surface has been developed. The rate constant of initial Cl atom fission has been calculated by canonical variational transition state theory as k = 1.45 × 1015 exp(-222 ± 9 kJ mol-1/RT) s-1 between 500 and 2000 K. A minimal kinetic model was developed to model the decomposition and major products. Oxidative decomposition was studied in nitrogen with O2 contents of 1, 6, 12, and 20 mol %. Increasing O2 to 6-8% increased the rate of decomposition of HCCP and decreased the yield of 8ClNP. Above 823 K, hexachlorobenzene (HCB) and CO became major products. The oxidative reaction has also been studied quantum chemically. At high O2 content (>∼10%), the rate of decomposition of HCCP declined as did yields of 8ClNP and HCB, but CO yields increased.
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Affiliation(s)
- Nirmala K Dharmarathne
- Process Safety and Environmental Protection Group, School of Engineering, The University of Newcastle , Callaghan, New South Wales 2308, Australia
| | - John C Mackie
- Process Safety and Environmental Protection Group, School of Engineering, The University of Newcastle , Callaghan, New South Wales 2308, Australia
| | - Eric M Kennedy
- Process Safety and Environmental Protection Group, School of Engineering, The University of Newcastle , Callaghan, New South Wales 2308, Australia
| | - Michael Stockenhuber
- Process Safety and Environmental Protection Group, School of Engineering, The University of Newcastle , Callaghan, New South Wales 2308, Australia
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6
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Horný Ľ, Quack M, Schaefer HF, Willeke M. Chlorine peroxide (Cl2O2) and its isomers: structures, spectroscopy, formation and thermochemistry. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1143984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Ľuboš Horný
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Martin Quack
- Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Henry F. Schaefer
- Center for Computational Chemistry, University of Georgia, Athens, GA, USA
| | - Martin Willeke
- Department of Materials, ETH Zürich, Zürich, Switzerland
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7
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Raghunath P, Lin MC. Ab initio chemical kinetics for the ClOO + NO reaction: Effects of temperature and pressure on product branching formation. J Chem Phys 2012; 137:014315. [DOI: 10.1063/1.4731883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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8
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Multiconfigurational study on the synchronous mechanisms of the ClO self-reaction leading to Cl or Cl2. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1194-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Schlöder T, Riedel S. Investigation of heterodimeric and homodimeric radical cations of the series: [F2O2]+, [F2Cl2]+, [Cl2O2]+, [F4]+, and [Cl4]+. RSC Adv 2012. [DOI: 10.1039/c1ra00804h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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10
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Zhu R, Lin M. Ab initio chemical kinetics for ClO reactions with HOx, ClOx and NOx (x=1,2): A review. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Lin JJ, Chen AF, Lee YT. UV Photolysis of ClOOCl and the Ozone Hole. Chem Asian J 2011; 6:1664-78. [DOI: 10.1002/asia.201100151] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Indexed: 11/10/2022]
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12
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Zhu RS, Lin MC. Ab initio chemical kinetics for reactions of ClO with Cl 2O 2 isomers. J Chem Phys 2011; 134:054307. [DOI: 10.1063/1.3541353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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13
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Xu ZF, Lin MC. Ab initio chemical kinetic study on Cl + ClO and related reverse processes. J Phys Chem A 2010; 114:11477-82. [PMID: 20923205 DOI: 10.1021/jp102947w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The reaction of ClO with Cl and its related reverse processes have been studied theoretically by ab initio quantum chemical and statistical mechanical calculations. The geometric parameters of the reactants, products, and transition states are optimized by both UMPW1PW91 and unrestricted coupled-cluster single and double excitation (UCCSD) methods with the 6-311+G(3df) basis set. The potential energy surface has been further refined (with triple excitations, T) at the UCCSD(T)/6-311+G(3df) level of theory. The results show that Cl(2) and O ((3)P) can be produced by chlorine atom abstraction via a tight transition state, while ClOCl ((1)A(1)) and ClClO ((1)A') can be formed by barrierless association processes with exothermicities of 31.8 and 16.0 kcal/mol, respectively. In principle the O ((1)D) atom can be generated with a large endothermicity of 56.9 kcal/mol; on the other hand, its barrierless reaction with Cl(2) can readily form ClClO ((1)A'), which fragments rapidly to give ClO + Cl. The rate constants of both forward and reverse processes have been predicted at 150-2000 K by the microcanonical variational transition state theory (VTST)/Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The predicted rate constants are in good agreement with available experimental data within reported errors.
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Affiliation(s)
- Z F Xu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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14
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Byun Y, Ko KB, Cho M, Namkung W, Lee K, Shin DN, Koh DJ. Reaction pathways of NO oxidation by sodium chlorite powder. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:5054-5059. [PMID: 19673306 DOI: 10.1021/es900152b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
NO oxidation is an important prerequisite step to assist selective catalytic reduction at low temperatures (< 250 degrees C). If sodium chlorite powder (NaClO2(s)) can oxidize NO to NO2, the injection of NaClO2(s) can be simply adapted to NO oxidation. Therefore, we explored the reaction pathways of NO oxidation by NaClO2(s). Known concentrations of NO and NO2 in N2 balance were injected into packed-bed reactor containing NaClO2(s) at 130 degreesC. NaClO2(s) oxidized NO to NO2 which reacts again with NaClO2(s) to produce OClO. Comparison of experimental data with simulation results demonstrates that each NO2 molecule removed by the reaction with NaClO2(s) generated one OClO molecule, which also oxidized NO to NO2 with the production of ClNO and ClNO2. Using these results, we conclude that the oxidation of NO by NaClO2(s) occurred by two pathways. One is through the direct reaction of NO with NaClO(s). The other is through both the reaction of NO with OlCO produced by the reaction of NO2 with NaClO2(s) and the reaction of NO with ClO produced by the reaction of NO with OClO.
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Affiliation(s)
- Youngchul Byun
- School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong Nam-gu Pohang 790-600, Republic of Korea
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15
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Zhou CW, Li ZR, Li XY. Kinetics and Mechanism for Formation of Enols in Reaction of Hydroxide Radical with Propene. J Phys Chem A 2009; 113:2372-82. [DOI: 10.1021/jp808574g] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chong-Wen Zhou
- College of Chemical Engineering and College of Chemistry, Sichuan University, Chengdu 610065, People’s Republic of China
| | - Ze-Rong Li
- College of Chemical Engineering and College of Chemistry, Sichuan University, Chengdu 610065, People’s Republic of China
| | - Xiang-Yuan Li
- College of Chemical Engineering and College of Chemistry, Sichuan University, Chengdu 610065, People’s Republic of China
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16
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Matus MH, Nguyen MT, Dixon DA, Peterson KA, Francisco JS. ClClO2 Is the Most Stable Isomer of Cl2O2. Accurate Coupled Cluster Energetics and Electronic Spectra of Cl2O2 Isomers. J Phys Chem A 2008; 112:9623-7. [DOI: 10.1021/jp806220r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Myrna H. Matus
- Department of Chemistry, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336
| | - Minh T. Nguyen
- Department of Chemistry, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336
| | - David A. Dixon
- Department of Chemistry, The University of Alabama, Shelby Hall, Box 870336, Tuscaloosa, Alabama 35487-0336
| | - Kirk A. Peterson
- Department of Chemistry, Washington State University, Pullman, Washington 99164-4630
| | - Joseph S. Francisco
- Department of Chemistry and Department of Earth & Atmospheric Sciences, Purdue University, West Lafayette, Indiana 47907-2084
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17
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Kosmas AM. Theoretical investigation of halogen-oxygen bonding and its implications in halogen chemistry and reactivity. Bioinorg Chem Appl 2007:46393. [PMID: 17713592 PMCID: PMC1939913 DOI: 10.1155/2007/46393] [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: 09/27/2006] [Revised: 01/18/2007] [Accepted: 03/29/2007] [Indexed: 12/03/2022] Open
Abstract
Trends in the properties of normal valent and multivalent halogen-oxygen bonding are examined for the isomers of the halogen polyoxide families of the types (YXO2) and (YXO3), Y = Cl, Br, I, H, CH3, X = Cl, Br, I. A qualitative model is formulated on the relationship between the X−O bond distance variations, the ionic character of the bonding, and the degree of halogen valence. The relative stability and enthalpy of formation of each species are also suggested to correlate with the ionic nature of the X−O bonding and the electrostatic character of the Y, YO fragments. In the model presented, halogen hypervalence is interpreted to be the result of partial p → d promotion of lone-pair valence electrons followed by the formation of two, four, or six additional pd hybrid bonds around the halogen atom.
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Affiliation(s)
- Agnie Mylona Kosmas
- Division of Physical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.
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18
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Liu J, Barker JR. On the Chaperon Mechanism: Application to ClO + ClO (+N2) → ClOOCl (+N2). J Phys Chem A 2007; 111:8689-98. [PMID: 17696323 DOI: 10.1021/jp072978p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamics of the ClO + ClO (+N(2)) radical complex (or chaperon) mechanism is studied by electronic structure methods and quasi-classical trajectory calculations. The geometries and frequencies of the stationary points on the potential energy surface (PES) are optimized at the B3LYP/6-311+G(3df) level of theory, and the energies are refined at the CCSD(T)/6-311+G(3df) (single-point) level of theory. Basis set superposition error (BSSE) corrections are applied to obtain 1.5 kcal mol(-1) for the binding energy of the ClO.N(2) van der Waals (VDW) complex. A model PES is developed and used in quasi-classical trajectory calculations to obtain the capture rate constant and nascent energy distributions of ClOOCl* produced via the chaperon mechanism. A range of VDW binding energies from 1.5 to 9.0 kcal mol(-1) are investigated. The anisotropic PES for the ClO.N(2) complex and a separable anharmonic oscillator approximation are used to estimate the equilibrium constant for formation of the VDW complex. Rate constants, branching ratios to produce ClOOCl, and nascent energy distributions of excited ClOOCl* are discussed with respect to the VDW binding energy and temperature. Interestingly, even for weak VDW binding energies, the N(2) usually carries away enough energy to stabilize the nascent ClOOCl*, although the VDW equilibrium constant is small. For stronger binding energies, the stabilization efficiency is reduced, but the capture rate constant is increased commensurately. The resulting rate constants for forming ClOOCl* from the title reaction are only weakly dependent on the VDW binding energy and temperature. As a result, the relative importance of the chaperon mechanism is mostly dependent on the VDW equilibrium constant. For the calculated ClO.N(2) binding energy of 1.5 kcal mol(-1), the VDW equilibrium constant is small, and the chaperon mechanism is only important at very high pressures.
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Affiliation(s)
- Jingyao Liu
- Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143, USA
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19
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Plenge J, Kühl S, Vogel B, Müller R, Stroh F, von Hobe M, Flesch R, Rühl E. Bond strength of chlorine peroxide. J Phys Chem A 2007; 109:6730-4. [PMID: 16834026 DOI: 10.1021/jp044142h] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The bond strength of chlorine peroxide (ClOOCl) is studied by photoionization mass spectrometry. The experimental results are obtained from the fragmentation threshold yielding ClO+, which is observed at 11.52 +/- 0.025 eV. The O-O bond strength D(o) is derived from this value in comparison to the first ionization energy of ClO, yielding D(o)298 = 72.39 +/- 2.8 kJ mol(-1). The present work provides a new and independent method to examine the equilibrium constant K(eq) for chlorine peroxide formation via dimerization of ClO in the stratosphere. This yields an approximation for the equilibrium constant in the stratospheric temperature regime between 190 and 230 K of the form K(eq) = 1.92 x 10(-27) cm3 molecules(-1) x exp(8430 K/T). This value of K(eq) is lower than current reference data and agrees well with high altitude aircraft measurements within their scattering range. Considering the error limits of the present experimental results and the resulting equilibrium constant, there is agreement with previous works, but the upper limit of current reference values appears to be too high. This result is discussed along with possible atmospheric implications.
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Affiliation(s)
- J Plenge
- Department of Chemistry, University of California at Berkeley, USA
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20
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Abstract
ClOOCl was prepared in situ in a temperature controlled photoreactor (v = 420 L) by photolyzing OClO/N2 mixtures in the wavelength range 300-500 nm at temperatures between 242 and 261 K and total pressures between 2 and 480 mbar. After switching off the lights, excess NO2 was added, and IR and UV spectra were monitored simultaneously as a function of time. By spectral stripping of all other known UV absorbers (in particular, other chlorine oxides and chlorine nitrate), we determined rate constants k-1 of the reaction ClOOCl (+M) --> ClO + ClO (+M) from the first-order decay of the residual UV absorption of ClOOCl at 246 and 255 nm. k-1,0 = [N2] x 7.6 x 10(-9) exp[(-53.6 +/- 6.0) kJ mol(-1)/RT] cm3 molecule(-1) s(-1) (2sigma) was derived for the low-pressure limiting rate constant. Application of Troe's expression for the limiting low-pressure rate constants of unimolecular decomposition reactions leads to E0 = Delta(r)H0(0)(ClOOCl-->ClO+ClO) = 66.4 +/- 3.0 kJ mol(-1). k-1,0 started to fall off from the pressure proportional low pressure behavior at p approximately 30 mbar; however, reliable extrapolation to the high pressure limit was not possible. The decomposition rate constants of ClOOCl were directly measured for the first time, and they are higher, depending on temperature and pressure, by factors between 1.5 and 4.2 as compared to experimental data on k-1 by Nickolaisen et al. [J. Phys. Chem. 1994, 98, 155] which were derived from the approach of ClO to thermal equilibrium with its dimer ClOOCl. Combination of the present dissociation rate constants with recommended temperature and pressure dependent data on the reverse reaction (k1) demonstrate inconsistencies between the dissociation and recombination rate constants. Summarizing laboratory data on k1 and k-1 above 250 K and field measurements on the ClO + ClO <= => ClOOCl equilibrium in the nighttime polar stratosphere close to 200 K, the expression Kc = k1/k-1 = 3.0 x 10(-27) exp(8433 K/T) cm3 molecule(-1) is derived for the temperature range 200-300 K.
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Affiliation(s)
- R Bröske
- Bergische Universität Wuppertal, Physikalische Chemie/FB C, D-42097 Wuppertal, Germany
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Knepp AM, Meloni G, Jusinski LE, Taatjes CA, Cavallotti C, Klippenstein SJ. Theory, measurements, and modeling of OH and HO2 formation in the reaction of cyclohexyl radicals with O2. Phys Chem Chem Phys 2007; 9:4315-31. [PMID: 17687479 DOI: 10.1039/b705934e] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The production of OH and HO(2) in Cl-initiated oxidation of cyclohexane has been measured using pulsed-laser photolytic initiation and continuous-laser absorption detection. The experimental data are modeled by master equation calculations that employ new G2(MP2)-like ab initio characterizations of important stationary points on the cyclo-C(6)H(11)O(2) surface. These ab initio calculations are a substantial expansion on previously published characterizations, including explicit consideration of conformational changes (chair-boat, axial-equatorial) and torsional potentials. The rate constants for the decomposition and ring-opening of cyclohexyl radical are also computed with ab initio based transition state theory calculations. Comparison of kinetic simulations based on the master equation results with the present experimental data and with literature determinations of branching fractions suggests adjustment of several transition state energies below their ab initio values. Simulations with the adjusted values agree well with the body of experimental data. The results once again emphasize the importance of both direct and indirect components of the kinetics for the production of both HO(2) and OH in radical + O(2) reactions.
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Affiliation(s)
- Adam M Knepp
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, CA 94551-0969, USA
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Quack M, Willeke M. Stereomutation Tunneling Switching Dynamics and Parity Violation in Chlorineperoxide Cl−O−O−Cl. J Phys Chem A 2006; 110:3338-48. [PMID: 16509660 DOI: 10.1021/jp055770h] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In a search for efficient spectroscopic avenues toward experiments on molecular parity violation, we investigate the stereomutation tunneling processes in the axially chiral chlorine isotopomers of Cl2O2 by the quasi-adiabatic channel reaction path Hamiltonian (RPH) approach and the corresponding parity violating potentials by means of quantum chemical calculations including our recently developed Multiconfiguration linear response (MC-LR) approach to electroweak quantum chemistry. The calculated ground-state torsional tunneling splittings for all isotopomers of Cl2O2 are much smaller than the parity violating energy differences Delta(pv)E between the enantiomers of these molecules and therefore parity violation is predicted to dominate the quantum dynamics of stereomutation at low energies. We also compare these with torsional ground-state tunneling splittings and parity violating energy differences of the whole series of axially chiral HXYH(+) isotopomers (with X, Y= Cl(+), O, S, Se, Te). A comparison with our previous results for the homologous molecule Cl2S2 shows that for Cl2O2 a spectroscopic high-resolution analysis should be easier and the energy region of large tunneling splittings should be more easily accessible by IR excitation. We thus propose a scheme using "tunneling switching" with vibrational excitation in order to carry out the measurement of time-dependent parity violation in superposition states of initially well-defined parity. We discuss the advantages and drawbacks of such an experiment that can be carried out entirely in the IR spectral range (for Cl2O2 or related molecules).
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Affiliation(s)
- Martin Quack
- Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
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Boakes G, Hindy Mok WH, Rowley DM. Kinetic studies of the ClO + ClO association reaction as a function of temperature and pressure. Phys Chem Chem Phys 2005; 7:4102-13. [PMID: 16474875 DOI: 10.1039/b510308h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The kinetics of the association reaction of ClO radicals: ClO + ClO + M --> Cl2O2+ M (1), have been investigated as a function of temperature T between 206.0-298.0 K and pressure p between 25-760 Torr using flash photolysis with time-resolved UV absorption spectroscopy. ClO radicals were generated following the photolysis of Br2/Cl2O mixtures in nitrogen diluent gas. Charge coupled device (CCD) detection of time resolved absorptions was used to monitor ClO radicals over a broad wavelength window covering the ClO (A 2Pi<-- X 2Pi) vibronic absorption bands. The high pass filtered ClO absorption cross sections were calibrated as a function of temperature between T = 206.0-320 K, and exhibit a negative temperature dependence. The ClO association kinetics were found to be more rapid than those reported in previous studies, with limiting low and high pressure rate coefficients, in nitrogen bath gas, k0 = (2.78 +/- 0.82) x 10(-32) x (T/300)(-3.99 +/- 0.94) molecule(-2) cm6 s(-1) and k(infinity) = (3.37 +/- 1.67) x 10(-12) x (T/300)(-1.49 +/- 1.81) molecule(-1) cm3 s(-1), respectively, (obtained with the broadening factor F(c) fixed at 0.6). Errors are 2sigma. The pressure dependent ClO association rate coefficients (falloff curves) exhibited some discrepancies at low pressures, with higher than expected rate coefficients on the basis of extrapolation from high pressures (p > 100 Torr). Reanalysis of data excluding kinetic data recorded below p = 100 Torr gave k0 = (2.79 +/- 0.85) x 10(-32) x (T/300)(-3.78 +/- 0.98) molecule(-2) cm6 s(-1) and k(infinity) = (3.44 +/- 1.83)x 10(-12) x (T/300)(-1.73 +/- 1.91) molecule(-1) cm3 s(-1). Potential sources of the low pressure discrepancies are discussed. The expression for k(0) in air bath gas is k0 = (2.62 +/- 0.80) x 10(-32) x (T/300)(-3.78 +/- 0.98) molecule(-2) cm6 s(-1). These results support upward revision of the ClO association rate coefficient recommended for use in stratospheric models, and the stratospheric implications of the results reported here are briefly discussed.
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Affiliation(s)
- Gavin Boakes
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ, UK
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Xu S, Lin MC. Computational Study on the Kinetics and Mechanism for the Unimolecular Decomposition of C6H5NO2and the Related C6H5+ NO2and C6H5O + NO Reactions†. J Phys Chem B 2005; 109:8367-73. [PMID: 16851982 DOI: 10.1021/jp046688+] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The kinetics and mechanisms for the unimolecular dissociation of nitrobenzene and related association reactions C(6)H(5) + NO(2) and C(6)H(5)O + NO have been studied computationally at the G2M(RCC, MP2) level of theory in conjunction with rate constant prediction with multichannel RRKM calculations. Formation of C(6)H(5) + NO(2) was found to be dominant above 850 K with its branching ratio > 0.78, whereas the formation of C(6)H(5)O + NO via the C(6)H(5)ONO intermediate was found to be competitive at lower temperatures, with its branching ratio increasing from 0.22 at 850 K to 0.97 at 500 K. The third energetically accessible channel producing C(6)H(4) + HONO was found to be uncompetitive throughout the temperature range investigated, 500-2000 K. The predicted rate constants for C(6)H(5)NO(2) --> C(6)H(5) + NO(2) and C(6)H(5)O + NO --> C(6)H(5)ONO under varying experimental conditions were found to be in good agreement with all existing experimental data. For C(6)H(5) + NO(2), the combination processes producing C(6)H(5)ONO and C(6)H(5)NO(2) are dominant at low temperature and high pressure, while the disproportionation process giving C(6)H(5)O + NO via C(6)H(5)ONO becomes competitive at low pressure and dominant at temperatures above 1000 K.
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Affiliation(s)
- Shucheng Xu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
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Zhu RS, Lin MC. Ab Initio Studies of ClOx Reactions: Prediction of the Rate Constants of ClO+NO for the Forward and Reverse Processes. Chemphyschem 2004; 5:1864-70. [PMID: 15648134 DOI: 10.1002/cphc.200400305] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The mechanisms for ClO+NO and its reverse reactions were investigated by means of ab initio molecular orbital and statistical theory calculations. The species involved were optimized at the B3LYP/6-311 +G(3df) level, and their energies were refined at the CCSD(T)/6-311+ G(3df)//B3LYP/6-311 + G(3df) level. Five isomers and the transition states among them were located. The relative stability of these isomers is ClNO2 > cis-ClONO > trans-ClONO > cis-OClNO>trans-OClNO. The heats of formation of the three most-stable isomers were predicted using isodesmic reactions by different methods. The predicted bimolecular reaction rate constant shows that, below 100 atm, the formation of Cl+NO2 is dominant and pressure-independent. The total rate constant can be expressed as: k(ClO+NO)= 1.43 x 10(-9)T(-083)exp(92/ T) cm3 molecule(-1)s(-1) in the temperature range of 200-1000 K, in close agreement with experimental data. For the reverse reaction, Cl+NO2-->ClNO2 and ClONO (cis and trans isomers), the sum of the predicted rate constants for the formation of the three isomers and their relative yields also reproduce the experimental data well. The predicted total third-order rate constants in the temperature range of 200-1000 K can be represented by: k0(He) = 4.89 x 10(-6)T(-5.85) exp(-796/T) cm6 molecule(-1)s(-1) and k0(N2) =5.72 x 10(-15)T(-5.80) exp(-814/T) cm6 molecule(-1)s(-1). The predicted high- and low-pressure limit decomposition rates of CINO2 in Ar in the temperature range 400-1500 K can be expressed, respectively, by: k-(ClNO2) = 7.25 x 10(19)T(-1.89) exp(-16875/T) s(-1) and kd(ClNO2) = 2.51 x 10(38)T(-6.8) exp(-18409/T) cm3 molecule(-1) s(-1). The value of k0(ClNO2) is also in reasonable agreement with available experimental data.
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Affiliation(s)
- R S Zhu
- Department of Chemistry Emory University 1515 Dickey Drive, Atlanta, GA 30322, USA.
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McKeachie JR, Appel MF, Kirchner U, Schindler RN, Benter T. Observation of a Heterogeneous Source of OClO from the Reaction of ClO Radicals on Ice. J Phys Chem B 2004. [DOI: 10.1021/jp049314p] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. R. McKeachie
- Department of Chemistry, 516 Rowland Hall, University of California, Irvine, California 92697-2025
| | - M. F. Appel
- Department of Biology, Chemistry and Environmental Science, Christopher Newport University, 1 University Place, Newport News, Virginia 23606
| | - U. Kirchner
- Ford Forschungszentrum Aachen GmbH, Süsterfeldstrasse 200, D-52072 Aachen, Germany
| | - R. N. Schindler
- Christian-Albrechts Universität zu Kiel, Institut für Physikalische Chemie, Ludewig-Meyn-Strasse 8, 24098 Kiel, Germany
| | - Th. Benter
- Bergische Universität Wuppertal, FB CMathematik und Naturwissenschaften, Gauss Strasse 20, 42097 Wuppertal, Germany
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Plenge J, Flesch R, Kühl S, Vogel B, Müller R, Stroh F, Rühl E. Ultraviolet Photolysis of the ClO Dimer. J Phys Chem A 2004. [DOI: 10.1021/jp049690+] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhu RS, Lin MC. Ab initio study of the HO2+NO reaction: Prediction of the total rate constant and product branching ratios for the forward and reverse processes. J Chem Phys 2003. [DOI: 10.1063/1.1619373] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Xu ZF, Lin MC. Ab initio studies of ClOx reactions. IX. Combination and disproportionation reactions of ClO and s-ClO3 radicals. J Chem Phys 2003. [DOI: 10.1063/1.1613632] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Barker JR, Golden DM. Master Equation Analysis of Pressure-Dependent Atmospheric Reactions. Chem Rev 2003; 103:4577-92. [PMID: 14664624 DOI: 10.1021/cr020655d] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John R Barker
- Department of Atmospheric, Oceanic and Space Sciences and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-2143, USA.
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Zhu RS, Lin MC. Ab initio studies of ClOx reactions. VIII. Isomerization and decomposition of ClO2 radicals and related bimolecular processes. J Chem Phys 2003. [DOI: 10.1063/1.1585027] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Zhu RS, Lin MC. Ab initiostudies of ClOx reactions. VII. Isomers of Cl2O3 and their roles in the ClO+OClO reaction. J Chem Phys 2003. [DOI: 10.1063/1.1565315] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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Zhu RS, Lin MC. Ab Initio Studies of ClOx Radical Reactions: V. Evidence for a New Path in the Cl + ClOOCl Reaction. J Phys Chem A 2003. [DOI: 10.1021/jp0218894] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R. S. Zhu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322
| | - M. C. Lin
- Department of Chemistry, Emory University, Atlanta, Georgia 30322
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