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Kinetics of the Toluene Reaction with OH Radical

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Research 2019年第1期2019卷 917-935页

作者： Rui Ming Zhang donald g.truhlar Xuefei Xu Center for Combustion Energy Department of Energy and Power Engineeringand Key Laboratory for Termal Science and Power Engineering of Ministry of EducationTsinghua UniversityBeijing 100084China Department of Chemistry Chemical Teory Centerand Minnesota Supercomputing InstituteUniversity of MinnesotaMinneapolisMN 55455-0431USA

We calculated the kinetics of chemical activation reactions of toluene with hydroxyl radical in the temperature range from 213 K to 2500 K and the pressure range from 10 Torr to the high-pressure limit by using multistructural variational transition state theory with the small-curvature tunneling approximation(MS-CVT/SCT)and using the system-specifc quantum Rice-RamspergerKassel *** reactions of OH with toluene are important elementary steps in both combustion and atmospheric chemistry,and thus it is valuable to understand the rate constants both in the high-pressure,high-temperature regime and in the low-pressure,low-temperature *** the experimental pressure conditions,the theoretically calculated total reaction rate constants agree well with the limited experimental data,including the negative temperature dependence at low *** fnd that the efect of multistructural anharmonicity on the partition functions usually increases with temperature,and it can change the calculated reaction rates by factors as small as 0.2 and as large as *** also fnd a large efect of anharmonicity on the zero-point energies of the transition states for the abstraction *** report that abstraction of H from methyl should not be neglected in atmospheric chemistry,even though the low-temperature results are dominated by *** calculated the product distribution,which is usually not accessible to experiments,as a function of temperature and pressure.

关键词： temperature. constants toluene

Unimolecular Reactions of E-glycolaldehyde Oxide and Its Reactions with One and Two Water Molecules

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Research 2024年第1期2023卷 809-824页

作者： Yan Sun Bo Long donald g.truhlar Department of Physics Guizhou UniversityGuiyang 550025China College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China Department of Chemistry Chemical Theory Centerand Supercomputing InstituteUniversity of MinnesotaMinneapolisMN 55455-0431USA

The kinetics of Criegee intermediates are important for atmospheric ***,the quantitative kinetics of Criegee intermediates are still very limited,especially for those with hydroxy ***,we calculate rate constants for the unimolecular reaction of E-glycolaldehyde oxide[E-hydroxyethanal oxide,E-(CH_(2)OH)CHOO],for its reactions with H_(2)O and(H_(2)O)_(2),and for the reaction of the E-(CH_(2)OH)CHOO…H_(2)O complex with H_(2)*** the highest level of electronic structure,we use W3X-L//CCSD(T)-F12a/cc-pVDZ-F12 for the unimolecular reaction and the reaction with water and W3X-L//DF-CCSD(T)-F12b/jun-cc-pVDZ for the reaction with 2 water *** the dynamics,we use a dual-level strategy that combines conventional transition state theory with the highest level of electronic structure and multistructural canonical variational transition state theory with small-curvature tunneling with a validated density functional for the electronic structure.

关键词： structure kinetics molecular

Reactions with Criegee intermediates are the dominant gas-phase sink for formyl fluoride in the atmosphere

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Fundamental Research 2024年第5期4卷 1216-1224页

作者： Yu Xia Bo Long Ai Liu donald g.truhlar College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China Department of Chemistry Chemical Theory Centerand Minnesota Supercomputing InstituteUniversity of MinnesotaMinneapolisMN 55455-0431United States

Atmospheric oxidation processes are of central importance in atmospheric climate *** is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reactions of hydroxyl radical with volatile organic molecules are *** we report rate constants for rapid reactions of formyl fluoride with Criegee *** rate constants are calculated by dual-level multistructural canonical variational transition state theory with small-curvature tunneling(DL-MS-CVT/SCT).The treatment contains beyond-CCSD(T)electronic structure calculations for transition state theory,and it employs validated density functional input for multistructural canonical variational transition state theory with small-curvature tunneling and for variable-reaction-coordinate variational transition state *** find that the M11-L density functional has higher accuracy than CCSD(T)/CBS for the HC(O)F+CH2OO and HC(O)F+anti-CH_(3)CHOO *** find significant negative temperature dependence in the ratios of the rate constants for HC(O)F+CH2OO/anti-CH_(3)CHOO to the rate constant for HC(O)F+*** also find that different Criegee intermediates have different rate-determining-steps in their reactions with formyl fluoride,and we find that the dominant gas-phase removal mechanism for HC(O)F in the atmosphere is the reaction with CH2OO and/or anti-CH_(3)CHOO Criegee intermediates.

关键词： Atmospheric oxidation capacity Criegee intermediates Formyl fluoride Reaction kinetics CCSDT(Q)/CBS calculations

Bioinspired mechanically interlocking holey graphene@SiO_(2)anode

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Interdisciplinary Materials 2022年第4期1卷 517-525页

作者： Fei Wang Xiaobin Liao Haoyu Wang Yan Zhao Jian Mao donald g.truhlar College of Materials Science and Engineering Sichuan UniversityChengduChina State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhanChina School of Materials Science and Engineering University of New South WalesSydneyNew South WalesAustralia The Institute of Technological Sciences Wuhan UniversityWuhanChina Department of Chemistry Chemical Theory CenterMinnesota Supercomputing InstituteUniversity of MinnesotaMinneapolisMinnesotaUSA

Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological *** by the biological structures in the wings of beetles,we synthesized a holey graphene@SiO_(2)anode with strong mechanical interlocking,characterized it electrochemically,and explained its performance by finite element analysis and density functional calcula*** mechanically interlocking structure enhances lithium-ion(Li^(+))storage by transmitting the strain from SiO_(2)to the holey graphene and by a mechano-electrochemical coupling *** interlocking fit hinders the abscission of SiO_(2)and the distinctive structure reduces the stress and strain of SiO_(2)during(de)*** positive mechano-electrochemical coupling effect preserves the amount of electrochemically active phase(LixSi)during cycles and facilitates Li+***,the capacity shows only a slight attenuation after 8000 cycles(cycling stability),and the specific capacity is~1200 mA h g^(−1)at 5 A/g(rate-performance).This study furnishes a novel way to design high-performance Li^(+)/Na+/K^(+)/Al3^(+)anodes with large volume expansion.

关键词： holey graphene mechanically interlocking mechano-electrochemical coupling effect simulation SiO_(2) anode

High-throughput predictions of metal-organic framework electronic properties:theoretical challenges,graph neural networks,and data exploration

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npj Computational Materials 2022年第1期8卷 1053-1062页

作者： Andrew S.Rosen Victor Fung Patrick Huck Cody T.O’Donnell Matthew K.Horton donald g.truhlar Kristin A.Persson Justin M.Notestein Randall Q.Snurr Department of Materials Science and Engineering University of CaliforniaBerkeleyCA94720USA Miller Institute for Basic Research in Science University of CaliforniaBerkeleyBerkeleyCA94720USA Materials Science Division Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Department of Chemical and Biological Engineering Northwestern UniversityEvanstonIL60208USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN37831USA Energy Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Department of Chemistry Chemical Theory Centerand Minnesota Supercomputing InstituteUniversity of MinnesotaMinneapolisMN55455USA Molecular Foundry Lawrence Berkeley National LaboratoryBerkeleyCA94720USA

With the goal of accelerating the design and discovery of metal–organic frameworks(MOFs)for electronic,optoelectronic,and energy storage applications,we present a dataset of predicted electronic structure properties for thousands of MOFs carried out using multiple density functional *** to more accurate hybrid functionals,we find that the widely used PBE generalized gradient approximation(ggA)functional severely underpredicts MOF band gaps in a largely systematic manner for semi-conductors and insulators without magnetic ***,an even larger and less predictable disparity in the band gap prediction is present for MOFs with open-shell 3d transition metal *** regards to partial atomic charges,we find that different density functional approximations predict similar charges overall,although hybrid functionals tend to shift electron density away from the metal centers and onto the ligand environments compared to the ggA point of *** more significant differences in partial atomic charges are observed when comparing different charge partitioning *** conclude by using the dataset of computed MOF properties to train machine-learning models that can rapidly predict MOF band gaps for all four density functional approximations considered in this work,paving the way for future high-throughput screening *** encourage exploration and reuse of the theoretical calculations presented in this work,the curated data is made publicly available via an interactive and user-friendly web application on the Materials Project.

关键词： charges electronic centers

Theoretical Study on Low Temperature Kinetics of Reaction Between Methanol and OH

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Theoretical Study on Low Temperature Kinetics of Reaction Be...

第十三届全国量子化学会议

作者： Lu gao Jingjing Zheng donald g.truhlar Xuefei Xu Center for Combustion Energy Tsinghua University

Under the assumption that the system is in the low-pressure plateau region, the rate constants and branching ratios of hydrogen abstraction reaction of methanol by OH radical in a wide temperature range of 30-2000 K have been calculated by using multistructural variational transition-state theory with small-curvature tunneling approximation(MS-CVT/SCT). Coupled cluster theory and multireference method were used to carry out the benchmark calculations of the stationary points on potential energy surfaces(PESs) to select the most appropriate density functional method for direct dynamics calculations of rate constants. We found that even under the low-pressure limit assumption, i.e., the system reaches local equilibrium only by the Liouville equation, and the pre-reaction complex is not needed to be considered, we still can observe the remarkably increasing rate constants with the decreasing temperatures at low temperature region. The remarkable negative temperature dependence(NTD) of rate constants mainly results from the tunneling effect as well as the large anharmonicity of high-frequency modes in the transition states, and it is not necessary to involve the formation of a long-lived hydrogen-bonded pre-reaction complex for the NTD phenomenon as Shannol et al. suggested [Nature Chemistry, 2013, 5, 745].

关键词： negative temperature dependence low temperature kinetics methonal tunneling anharmonicity

Kinetics of OH + ketohydroperoxides in the low-temperature oxidation of n-pentane: Multi-path variational transition state theory

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Kinetics of OH + ketohydroperoxides in the low-temperature o...

第十三届全国量子化学会议

作者： Lili Xing Junwei Lucas Bao Feng Zhang donald g.truhlar National Synchrotron Radiation Laboratory University of Science and Technology of China Department of Chemistry University of Minnesota

Ketohydroperoxides(KHP) are important intermediates in the low-temperature oxidation of n-alkanes, and their fate has an important effect on low-temperature-oxidation reactivity [1]. They have hydroperoxy groups with low O–O bond energy and decompose easily to OH and alkoxy radicals, allowing low-temperature chain branching;but H abstraction reactions on ketohydroperoxides can play a significant role, decreasing the chain branching effect of the competing initiation reactions. However, these H abstraction rates are unavailable experimentally. Thus kinetics of OH + ketohydroperoxides resulting from n-pentane oxidation were studied in this work. With multistructural variational transition state theory(MS-VTST) and multi-path variational transition state theory(MP-VTST)[2], and with multidimensional tunneling(MT) approximations [3], the rate coefficients of this reaction system are computed accurately in the present work. We also explore the OH addition reaction and the further decomposition of the product of the addition reaction. The pressure dependences of the addition and dissociation reactions are studied by the system-specific quantum RRK method[4].

关键词： Multistructural microcanonical variational transition state theory (MS-VTST) quantum Rice-Ramsperger-Kassel (QRRK) Anharmonicity Branching fractions

Revised M06-L Functional

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Revised M06-L Functional

第十五届全国化学动力学会议

作者：王颖 Xinsheng Jin Haoyu S.Yu donald g.truhlar Xiao He School of Chemistry and Molecular Engineering State Key Laboratory of Precision SpectroscopyEast China Normal University Department of Chemistry Chemical Theory CenterNanoporous Materials Genome Centerand Minnesota Supercomputing InstituteUniversity of Minnesota NYU-ECNU Center for Computational Chemistry at NYU Shanghai

M06-L has proven to be one of the most accurate local functionals currently available,but it has room for improvement with regard to numerical stability and overall *** we present a revised M06-L functional,named revM06-L,which gives both smoother potential energy curves and improved overall accuracy,especially for chemical reaction barrier heights,noncovalent interactions,and solid-state *** obtained the revM06-L functional by optimizing against a larger database than had been used for M06-L and by using smoothness *** mean unsigned error（MUE） of revM06-L on 422 chemical energies is 3.07 kcal/mol,which is improved from 3.57 kcal/mol calculated by *** MUE of revM06-L for the chemical reaction barrier height database（BH76） is 1.98 kcal/mol,which is improved by more than a factor of 2 with respect to the M06-L *** revM06-L functional gives the best result among local functionals tested for the noncovalent interaction database（NC51）,with an MUE of only 0.36 kcal/mol,and the MUE of revM06-L for the solid-state lattice constant database（LC17） is about half of that for *** revM06-L functional also predicts more accurate results than M06-L in 6 out of 7 diversified test sets not used for *** conclude that the revM06-L functional is well suited for a broad range of applications in chemistry and condensed matter physics.

关键词： DFT local functional M06-L barrier height noncovalent interactions chemical energies

Revised M06-L Functional

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Revised M06-L Functional

第十三届全国量子化学会议

作者： Ying Wang Xinsheng Jin Haoyu S.Yu donald g.truhlar Xiao He School of Chemistry and Molecular Engineering East China Normal University

M06-L has proven to be one of the most accurate local functionals currently available,but it has room for improvement with regard to numerical stability and overall *** we present a revised M06-L functional,named revM06-L,which gives both smoother potential energy curves and improved overall accuracy,especially for chemical reaction barrier heights,noncovalent interactions,and solid-state *** obtained the revM06-L functional by optimizing against a larger database than had been used for M06-L and by using smoothness *** mean unsigned error(MUE) of revM06-L on 422 chemical energies is 3.07 kcal/mol,which is improved from 3.57 kcal/mol calculated by *** MUE of revM06-L for the chemical reaction barrier height database(BH76) is 1.98 kcal/mol,which is improved by more than a factor of 2 with respect to the M06-L *** revM06-L functional gives the best result among local functionals tested for the noncovalent interaction database(NC51),with an MUE of only0.36 kcal/mol,and the MUE of revM06-L for the solid-state lattice constant database(LC17) is about half of that for *** revM06-L functional also predicts more accurate results than M06-L in 6 out of 7 diversified test sets not used for *** conclude that the revM06-L functional is well suited for a broad range of applications in chemistry and condensed matter physics.

关键词： DFT local functional M06-L barrier height noncovalent interactions chemical energies