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First-principles calculations of elasticity of minerals at high temperature and pressure

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Science China Earth Sciences 2016年第6期59卷 1107-1137页

作者： WU ZhongQing WANG WenZhong Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space ScienceUniversity of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory Mengcheng 233527China

The elasticity of minerals at high temperature and pressure （PT） is critical for constraining the composition and temperature of the Earth＇s interior and understand better the deep water cycle and the dynamic Earth. First-principles calcula- tions without introducing any adjustable parameters, whose results can be comparable to experimental data, play a more and more important role in investigating the elasticity of minerals at high PT mainly because of （1） the quick increasing of computational powers and （2） advances in method. For example, the new method reduces the computation loads to one-tenth of the traditional method with the comparable precise as the traditional method. This is extraordinarily helpful because first-principles calculations of the elasticity of minerals at high PT are extremely time-consuming. So far the elasticity of most of lower mantle minerals has been investigated in detail. We have good idea on the effect of temperature, pressure, and iron concentration on elasticity of main minerals of the lower mantle and the unusual softening in bulk modulus by the spin crosso- ver of iron in ferropericlase. With these elastic data the lower mantle has been constrained to have 10-15 wt% ferropericlase, which is sufficient to generate some visible effects of spin crossover in seismic tomography. For example, the spin crossover causes that the temperature sensitivity of P wave at the depth of -1700 km is only a fraction of that at the depth of -2300 kin. The disruptions of global P wave structure and of P wave image below hotspots such as Hawaii and Iceland at similar depth are in consistence with the spin crossover effect of iron in ferropericlase. The spin crossover, which causes anomalous ther- modynamic properties of ferropericlase, has also been found to play a control role for the two features of the large low shear velocity provinces （LLSVPs）： the sharp edge and high elevation up to 1000 km above core-mantle boundary. All these results clearly su

关键词： Mantle temperature Mantle composition Composition of Earth's core ab initio method

Structure and bonding properties of Y doped Σ37 grain boundary in alumina

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Chinese Physics B 2009年第3期18卷 1181-1187页

作者：王亚斌张刚刘明杰陈湘陇陈军 School of Aerospace Science and Engineering Beijing Institute of Technology China Aerospace Engineering Consultation Center Institute of Applied Physics and Computational Mathematics

The microscopic structures and the bonding properties of Y-doped and undoped （011^-8）/[044^-1]/180° （∑37） grain boundaries in alumina are investigated by using ab initio method. The formation energy of grain boundary and the segregation energy of Y to grain boundary are acquired. Electronic structures, potential distributions, bond orders and effective charges of Y-doped and undoped ∑37 GB systems are calculated. Our results reveal that the higher strength Y-O bond than Al-O bond is ascribed to the hybridization of Y（4p, 3d） with O（2s）. Meanwhile, dopant Y also causes a change in potential distribution in the grain boundary region, thereby further affecting the transport property of ceramic alumina.

关键词： grain boundary alumina Y doping ab initio method

Theoretical study on tetrazole and its derivatives (3) MP2 and thermodynamic calculations of amino derivatives of tetrazole

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Chinese Journal of Chemistry 1999年第2期17卷 114-124页

作者：陈兆旭肖鹤鸣高宝华 Department of Chemistry Nanjing university of Science and Technology Nanjing Jiangsu 210094 China

Fully optimized geometries and electronic structures of amino derivatives of tetrazole are obtained at MP2/6-31G* level. The tetrazole rings are planar and aromatic for all the amino derivatives of tetrazole. The amino group is not co-planar with the ring and its conformation is mainly determined by the lone pair electronic repulsion between the substituents and the ring. N(4) atom is more negatively charged and is the most probable coordination site. The energy gaps between LUMOs and HOMOs of 2H-aminotetrazoles and C-aminotetrazole neutrals are smaller than those of the corresponding 1H-isomers and N-aminotetrazole neutrals respectively. The IR frequencies, thermodynamic properties and temperature-dependent functions for heat capacities in the fom (a + bT + cT2) in the 300–1000K range are reported.

关键词： Tetrazole derivatives ab initio method molecular geometry IR spectra thermodynamic property

ab initio study on the mechanism of rhodium-complex-catalyzed carbonylation of methanol to acetic acid

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Science China Chemistry 2001年第5期44卷 465-472页

作者：雷鸣冯文林郝茂荣冀永强徐振锋 Department of Chemistry Faculty of Science Beijing University of Chemical Technology Beijing China

The whole catalytic cycle of the carbonylation of methanol to acetic acid catalyzed by Rh complex is theoretically studied. All structural geometries of reactant, intermediates, transition states and product are optimized at HF/LANL2DZ level under the ECP approximation. The potential energy profiles for elementary reactions of carbonylation are calculated respectively. The transition states are further confirmed by having one and only one imaginary vibrational frequency. The results indicate that the activation energy values of CHin3I oxidative addition, carbonyl insertion and CH3COI reductive elimination fundamental steps are 216.03, 128.10 and 126.55 kJ/mol, respectively; and that the CH3I oxidative addition step is predicted to be the rate-determining one.

关键词： rhodium complex carbonylation ab initio method effective core potential

Synthesis,Crystal Structure and Quantum Chemistry of a Hydration Dibenzyltin Dichloride

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Chinese Journal of Structural Chemistry 2009年第5期28卷 597-601页

作者：王剑秋张复兴邝代治冯泳兰张志坚许志锋 Department of Chemistry and Materials Science Hunan Key Laboratory of Functional Organometallic MaterialsHengyang Normal UniversityHengyang Hunan 421008China Department of Chemistry and Materials Science Hunan Key Laboratory of Functional Organometallic MaterialsHengyang Normal UniversityHengyang Hunan 421008 China Department of Chemistry and Materials Science Hunan Key Laboratory of Functional Organometallic MaterialsHengyang Normal UniversityHengyang Hunan 421008 China Department of Life Science Hengyang Normal UniversityHengyang Hunan 421008 China

A novel organotin hydration dibenzyltin dichloride has been synthesized and its crystal structure was determined by X-ray diffraction. The crystal belongs to monoclinic, space group Pc with a = 1.1918（5）, b = 0.6199（2）, c = 1.1074（5）nm, β = 106.899（7）°, V= 0.7828（8）nm3, Z = 2, Dc = 1.654 g/cm3,μ（MoKa） = 19.59 cm^-1, F（000） = 384, R = 0.0564 and RwR = 0.1427. The Sn-C bonds are 0.2140（9） and 0.2152（5） nm, Sn-Cl are 0.2385（4） and 0.2497（3） nm, and Sn-O is 0.2388（7） nm. The tin atom is five-coordinated in a distorted trigonal bipyramidal configuration. The study on the title complex has been performed with quantum chemistry calculation by means of G98W package on the Lanl2dz basis set. The stability of the complex as well as the orbital energies and composition characteristics of some frontier molecular orbitals has been investigated.

关键词： dibenzyltin dichloride hydration synthesis crystal structure ab initio method

Synthesis,Crystal Structure and Quantum Chemistry of Dibutyltin 3,4-Dimethoxybenzotate Compound

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Chinese Journal of Structural Chemistry 2010年第10期29卷 1529-1535页

作者：张复兴王剑秋邝代治冯泳兰许志锋张志坚张可 Department of Chemistry and Material Science Hengyang Normal University Key Laboratory of Functional Organometallic Materials of Hengyang Normal University College of Hunan Province Key Laboratory of Functional Organometallic Materials of Hengyang Normal University College of Hunan Province

The dibutyltin 3,4-dimethoxybenzotate compound {[（3,4-（CH3O）2C6H3COO） Sn（Bu-n）2]2O}2 has been synthesized by the reaction of dibutyltin oxide with 3,4-dimethoxybenzoic acid. Its structure was determined by X-ray single-crystal diffraction. The crystal belongs to the triclinic system,space group P1 with a = 1.2003（2）,b = 1.2821（3）,c = 1.3666（3） nm,α = 80.50（3）,β = 65.56（3）,γ = 73.36（3）°,Z = 2,V = 1.8318（6） nm3,Dc = 1.530 Mg·m-3,μ（MoKa） = 1.413 mm-1,F（000） = 860,R = 0.0554 and wR = 0.1092. In the complex,each tin atom adopts a distorted tigonal bipyramidal structure,and the dimer structure is shaped by one Sn2O2 planar four-membered ring. The stabilities of the title complex,along with its orbital energies and composition characteristics of some frontier molecular orbitals have been investigated by means of quantum chemistry calculation methods.

关键词： dibutyltin 3,4-dimethoxybenzoic acid synthesis crystal structure ab initio method

ab initio MO Studies on the Reaction Mechanism for Carbonyl Insertion Catalyzed by Carbonyl Cobalt Complex

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Chemical Research in Chinese Universities 2000年第1期16卷 31-35页

作者： LEI Ming FENG Wen-lin and XU Zhen-feng (Department of Applied Chemistry, Beijing University of Chemical Technology,Beijing 100029, P. R. China Department of Chemistry, Beijing Normal University, Beijing 100875, P. R. China) 北京化工大学北京 100029 北京师范大学北京 100875

ab initio method, under the effective core potential(ECP) approximation at HF/LANL2DZ level, has been employed to study the reaction mechanism of the carbonyl insertion of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)_3. The two reaction paths have been discussed. The calculated potential energy barriers for the carbonyl migration and the ethyl group migration are 105. 0 kJ/mol and 39. 17 kJ/mol, respectively. The results indicate that the reaction path via ethyl migration is more energetically favorable than that via carbonyl insertion.

关键词： Carbonyl Cobalt Hydroformylation ab initio method Effective core potential

A Theoretical Study on the Hydrogen-bonded Dimers of HNCO Molecules

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Chinese Journal of Structural Chemistry 1994年第4期13卷 312-315页

作者： Wang Yan Feng Wen-Lin Zhang Shao-Wen Zhu Wei-Xin(Chemistry Department, Beijing Normal University, Beijing 100875)

ab initio method has been employed to investigate the hydrogenbond between two HNCO molecules. Two types of hydrogen-bondings in HNCO dimers have been found, one type is N-H…O, the other is N-H…N. The latter is a little stabler than that of the former. The stabilization energies of the two types of dimers are estimated to be 13KJ/mol-21KJ/mol.

关键词： HNCO hydrogen-bond ab initio method

An ab-initio study of a^1B_(3u)→X^1A_g transition in a neutral molecular N_2 dimer

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Journal of Harbin Institute of Technology(New Series) 2001年第1期8卷 59-62页

作者：申作春董蕴华高惠德马祖光

Presents the ab initio calculations performed for different symmetry groups of neutral molecular N 2 dimer, and the calculation of ground state and low lying singlet excited states for each symmetry group and concludes from the results that there is an electric dipole transition between X 1A g and a 1B 3u (singlet singlet) excited states belonging to D 2h group symmetry, and discusses the vibrational energy levels and emission spectra calculates for this transition.

关键词： ab initio method HF theory dimer normal vibrational modes