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transition state and formation process of Stone–Wales defects in graphene

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Chinese Physics B 2022年第3期31卷 424-427页

作者： Jian-Hui Bai Yin Yao Ying-Zhao Jiang School of Aviation and Mechanical Engineering Changzhou Institute of Technology Changzhou 213032China School of Sciences Changzhou Institute of Technology Changzhou 213032China Department of Physics Guizhou Minzu University Guiyang 550025China

Stone–Wales(SW) defects are possibly formed in graphene and other two-dimensional materials, and have multiple influence on their physical and chemical properties. In this study, the transition state of SW defects in graphene is determined with the fully discrete Peierls theory. Furthermore, the atomic formation process is investigated by means of ab-initio simulations. The atomic structure change and energetics of the SW transformation are revealed. It is found that the transition state is at the SW bond rotation of 34.5°and the activation energy barrier is about 12 eV. This work provides a new method to investigate SW transformations in graphene-like materials and to explore unknown SW-type defects in other 2D materials.

关键词： graphene Stone–Wales(SW)defect transition state fully discrete Peierls theory

Theoretical Study on the transition state of N-nitropyrazoles Rearrangement Reaction

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Chinese Journal of Structural Chemistry 2018年第4期37卷 531-542页

作者：杨峰李永祥党鑫郭恒杰柴笑笑 School of Chemical Engineering and Environment North University of China

Theoretical studies on the rearrangement reactions of nitropyrazoles have beeninvestigated. In order to gain a better understanding of the intermediate process of rearrangementreactions, the transition states of the rearrangement reactions were obtained by TS method at theB3LYP/6-311G（d, p） level of theory. The natural bond orbital charge, electrostatic potential andfrontier molecular orbital of the molecules in the process of rearrangement were analyzed, and thesolvent effect was also discussed. The rearrangement of nitropyrazoles involves two transitionstates and one intermediate, and the nitro group and hydrogen atom are two transfer groups forrearrangement reactions. The migration of these two groups leads to the change of chargedistribution and molecular structure. The structural changes of the molecules in different solventsare not significant, but the dipole moment of the molecule has obvious change.

关键词： nitropyrazoles rearrangement transition state density functional theory (DFT)

Combined multi-level quantum mechanics theories and molecular mechanics study of water-induced transition state of OH^- + CO_2 reaction in aqueous solution

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Chinese Physics B 2017年第10期26卷 200-204页

作者：李琛牛美兴刘鹏李永方王敦友 College of Physics and Electronics Shandong Normal University

The presence of a solvent interacting with a system brings about qualitative changes from the corresponding gas-phase reactions. A solvent can not only change the energetics along the reaction pathway, but also radically alter the reaction mechanism. Here, we investigated the water-induced transition state of the OH^-＋CO2→HCO3^- reaction using a multi-level quantum mechanics and molecular mechanics method with an explicit water model. The solvent energy contribution along the reaction pathway has a maximum value which induces the highest energy point on the potential of mean force. The charge transfer from OH^- to CO2 results in the breaking of the OH^- solvation shell and the forming of the CO2 solvation shell. The loss of hydrogen bonds in the OH^- solvation shell without being compensated by the formation of hydrogen bonds in the CO2 solvation shell induces the transition state in the aqueous solution. The calculated free energy reaction barrier at the CCSD（T）/MM level of theory, 11.8 kcal/mol, agrees very well with the experimental value, 12.1 kcal/mol.

关键词： transition state reaction pathway free energy barrier solvent effect

transition state and Catastrophe Set

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Chemical Research in Chinese Universities 1991年第1期7卷 65-66页

作者： Fang Jianyun Tang Auchin (Institute of Theoretical Chemistry, Jilin University, Changchun)

The study on transition states is one of the most important pathways to understand the essence of chemical reactions. With the development of femtoseeond pulse technique, Zewail et al. have carried out a number of experimental studies on the transition states, while the theoretical chemists has a great interest in the topic. In the previous

关键词： transition state Catastrophe set state variable

Adsorption and desorption of acetone by TiO_(2) clusters:transition state theory and sensing analysis

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ChemPhysMater 2023年第4期2卷 351-355页

作者： Mudar Ahmed Abdulsattar Tasneem Hassan Mahmood Hussein Hakim Abed Hayder M.Abduljalil Department of Pharmacy Al-Rasheed University CollegeBaghdad 10011Iraq Ministry of Science and Technology Baghdad 10011Iraq Department of Physics College of Science for WomenUniversity of BaghdadBaghdad 10011Iraq Department of Physics College of ScienceUniversity of BabylonBabylon 51005Iraq

TiO_(2) cluster sensitivity to acetone adsorption using transition state theory is ***_(10)O_(20) cluster is used to perform the calculations using density functional theory with dispersion *** state and transition state are calculated via thermodynamic energies,i.e.,Gibbs free energy of adsorption and *** rate,response,response time,and recovery time as a function of temperature and acetone concentration are *** burning in the air due to autoignition is considered using a logistic *** results of the theory are compared with available experimental findings that revealed the quality of both theoretical and experimental *** response time decreases with respect to acetone *** the other hand,the recovery time in the desorption phase increases with acetone *** temperature of maximum response is 356℃,while the maximum response value is 2.9.

关键词： TiO_(2) Acetone transition state Sensor Density functional theory

Density Functional Theory and MP2 Calculations of the transition states and Reaction Paths on Coupling Reaction of Methane through Plasma

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Chinese Journal of Chemistry 2004年第5期22卷 430-433页

作者：杨恩翠赵小军田鹏郝金库 College of Chemistry & Life Science Tianjin Normal University Tianjin 300074 Chin

The two possible reaction paths of producing ethane on coupling reaction of methane through plasma were theoretically investigated by B3LYP and MP2 methods with 6-311G* respectively and further compared with the previous results calculated from B3LYP/6-31G*. The new investigated results consistently confirmed the previous conclusion. And the influences of the calculation methods and basis sets on the calculated results were also dis-cussed.

关键词： density functional theory MP2 transition state reaction path methane plasma

Theoretical Study of Reaction Paths and transition states on Conversion Methane into C_2 Hydrocarbons Through Plasma

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Chinese Journal of Chemical Engineering 2007年第1期15卷 44-50页

作者：王保伟杨恩翠许根慧郝金库 Key Laboratory for Green Chemical Technology of state Education Ministry School of Chemical Engineering &TechnologyTianjin UniversityTianjin 300072China College of Chemistry and Life Sciences Tianjin Normal UniversityTianjin 300074China College of Chemistry and Life Sciences Tianjin Normal UniversityTianjin 300074 China

The direct synthesis of C2 hydrocarbons （ethylene, acetylene and ethane） from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be real-ized through plasma reaction. In order to explore the reaction process and mechanism, the possible reaction paths （1）—（4） were proposed on coupling reaction of methane through plasma and studied theoretically using semi-PM3 method [PM3 is parameterization method of modified neglect of diatomic overlap （MNDO）] including determining the transition state, calculating the activation energy and thermodynamic state functions and analyzing the bond or-der and intrinsic reaction coordinate. The reaction heat results indicate that the reactions （2） and （4） are exothermic, while reactions of （1） and （3） are endothermic. The activation energy results show that activation energy for reac-tions （1） and （2） was much lower than that of reaction paths （3） and （4）. Therefore, paths （1） and （2） is the favorable reaction path energetically. More interestingly by comparing the intrinsic reaction coordinated （IRC） of the reaction paths （1） and （2）, it is found that the variations of bond lengths in reaction path （1） has a crucial effect on the poten-tial energy, while in reaction path （2）, the adjustment of the system geometry also contributes to the whole potential energy of the system.

关键词： reaction path transition state methane plasma PM3

Shock Induced Chemical Reactions of Intermetallic Mixture of Nickel and Aluminum and Associated transition states

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Journal of Materials Science and Chemical Engineering 2021年第4期9卷 60-67页

作者： Vindhya Narayanan Sathya Hanagud Georgia Institute of Technology Atlanta GA USA

In this paper, numerical simulation of shock-induced chemical reactions of intermetallic mixtures is discussed. Specifically, the paper focuses on intermetallic mixture of nickel and aluminum. To initiate the chemical reactions, the thermal input or the shockwave should supply the energy to take the reactants, mixture of nickel and aluminum, to the transition state. Thus, for any numerical simulation or analysis of the shock or thermally induced chemical reaction in a continuum scale or a meso scale, it is necessary to identify the transition state. The transition state for the intermetallic mixture of nickel and the aluminum is identified in this paper and a result of the numerical simulation of the shock-induced chemical reaction, in a continuum scale is presented. The numerical solutions clearly show the chemical reactions, release of heat energy, increase of the temperature and the formation of products, following the transition state and the resulting shock-induced chemical reaction of a binary intermetallic energetic mixture of nickel and aluminum. The studies also show that the collapse of porosity is a mechanism that takes the reactants to the transition state, in shock-induced chemical reactions of binary intermetallic mixtures.

关键词： transition state Shock Induced Chemical Reaction Void Collapse NIckel-Aluminum Energetic Mixture

Solvent effects and potential of mean force study of the SN2 reaction of CH3F+CN-in water

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Chinese Physics B 2018年第3期27卷 238-243页

作者： Chen Li Peng Liu Yongfang Li Dunyou Wang College of Physics and Electronics Shandong Normal University Jinan 250014 China

We used a combined quantum mechanics and molecular mechanics （QM/MM） method to investigate the solvent effects and potential of mean force of the CH3F＋CN- reaction in water. Comparing to gas phase, the water solution substantially affects the structures of the stationary points along the reaction path. We quantitatively obtained the solvent effects＇ contributions to the reaction： 1.7 kcal/mol to the activation barrier and -26.0 kcal/mol to the reaction free energy. The potential mean of force calculated with the density functional theory/MM theory has a barrier height at 19.7 kcal/mol, consistent with the experimental result at 23.0 kcal/mol; the calculated reaction free energy at -43.5 kcal/mol is also consistent with the one estimated based on the gas-phase data at -39.7 kcal/mol.

关键词： transition state quantum mechanics and molecular mechanics solvent effect potential of mean force