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Ab initio potential energy surface and anharmonic vibration spectrum of NF_(3)^(+)
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作者 陈艳南 徐建刚 +3 位作者 范江鹏 马双雄 郭甜 张云光 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期327-333,共7页
Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction... Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction(VCI). Based on an iterative algorithm, the surfaces(SURF) program adds automatic points to the lattice representation of the potential function, the one-dimensional and two-dimensional PESs are calculated after reaching a convergence threshold, finally the smooth image of the potential energy surface is fitted. The PESs accurately account for the interaction between the different modes, with the mode q_(6) symmetrical stretching vibrations having the greatest effect on the potential energy change of the whole system throughout the potential energy surface shift. The anharmonic frequencies are obtained when the VCI matrix is diagonalized. Fundamental frequencies, overtones, and combination bands of NF_(3)^(+) are calculated, which generate the degenerate phenomenon between their frequencies. Finally, the calculated anharmonic frequency is used to plot the infrared spectra.Modal antisymmetric stretching ν_(5) and symmetric stretching ν_(6) exhibit a phenomenon of large-intensity borrowing. This study can provide data to support the characterization in the laboratory. 展开更多
关键词 ab initio methods potential energy surfaces vibration frequencies coupled resonance infrared spectra
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Ab Initio MO Studies on the Reaction Mechanism for Carbonyl Insertion Catalyzed by Carbonyl Cobalt Complex 被引量:1
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作者 LEI Ming FENG Wen-lin +1 位作者 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) 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2000年第1期31-35,共5页
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 carbo... 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. 展开更多
关键词 Carbonyl Cobalt HYDROFORMYLATION ab initio method Effective core potential
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Ab initio investigation of the mechanical properties of copper
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作者 刘悦林 桂漓江 金硕 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第9期404-409,共6页
Employing the ab initio total energy method based on the density functional theory with the generalized gradient approximation, we have systematically investigated the theoretical mechanical properties of copper (Cu... Employing the ab initio total energy method based on the density functional theory with the generalized gradient approximation, we have systematically investigated the theoretical mechanical properties of copper (Cu). The theoretical tensile strengths are calculated to be 25.3 GPa, 5.9 GPa, and 37.6 GPa for the fcc Cu single crystal in the [001], [110], and [111] directions, respectively. Among the three directions, the [110] direction is the weakest one due to the occurrence of structure transition at the lower strain and the weakest interaction of atoms between the (110) planes, while the [111] direction is the strongest direction because of the strongest interaction of atoms between the (111) planes. In terms of the elastic constants of Cu single crystal, we also estimate some mechanical quantities of polycrystalline Cu, including bulk modulus B, shear modulus G, Young's modulus Ep, and Poisson's ratio ~. 展开更多
关键词 COPPER theoretical tensile strength ab initio method
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An ab-initio study of a^1B_(3u)→X^1A_g transition in a neutral molecular N_2 dimer
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作者 申作春 董蕴华 +1 位作者 高惠德 马祖光 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第1期59-62,共4页
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 conclude... 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. 展开更多
关键词 ab initio method HF theory DIMER normal vibrational modes
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A NEW AB INITIO CALCULATION METHOD OF INNER-SPHERE REORGANIZATION ENERGY
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作者 Yu Xiang BU Xin Yu SONG Yu Hua ZHANG(Department of Chemistry. Qufu Normal University,Qufu,273165) 《Chinese Chemical Letters》 SCIE CAS CSCD 1995年第6期491-494,共4页
On the basis of the-improved self-exchange model of reorganization phenomenon and accurate potential functions from ab initio calculation at HFSCF 6-31G* and DZP levels a new calculation method was,presented for the i... On the basis of the-improved self-exchange model of reorganization phenomenon and accurate potential functions from ab initio calculation at HFSCF 6-31G* and DZP levels a new calculation method was,presented for the inner-sphere reorganization energy, values for diatomic molecular redox couples in gas phase electron transfer process have been calculated. Results agree well with the experimental data, and the effectiveness and importance of this method have been demonstrated for calculation of inner-sphere reorganization energy in gas phase electron transfer process. 展开更多
关键词 ab A NEW ab initio CALCULATION METHOD OF INNER-SPHERE REORGANIZATION ENERGY
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Elastic and Optoelectronic Properties of KCdF3:ab initio Calculations through LDA/GGA/TB-mBJ within FP-LAPW Method
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作者 K. Ephraim Babu N. Murali +2 位作者 K. Vijaya Babu B. Kishore Babu V. Veeraiah 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第1期108-112,共5页
Ab initio calculations are performed on the electronic, structural, elastic and optical properties of the cubic per- ovskite KCdF3. Tile Kohn Sham equations are solved by applying the full potential linearized augment... Ab initio calculations are performed on the electronic, structural, elastic and optical properties of the cubic per- ovskite KCdF3. Tile Kohn Sham equations are solved by applying the full potential linearized augmented plane wave (FP-LAPW) method. The exchange correlation effects are included through the local density approximation (LDA ), generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) exchange potential The calculated lattice constant is in good agreement with the experimental result. The elastic properties such as elastic constants, anisotropy factor, shear modulus, Young's modulus and Poisson's ratio are calculated. KCdF3 is ductile and elastically anisotropic. The calculations of the electronic band structure, density of states (DOS) and charge density show that this compound has an indirect energy band gap (M-F) with a mixed ionic and covalent bonding. The contribution of the different bands is analyzed from the total and partial density of states curves. Optical response of the dielectric functions, optical reflectivity, absorption coefficient, real part of optical conductivity, refractive index, extinction coefficient and electron energy loss, are presented for the energy range of O-40eV. The compound KCdF3 can be used for high-frequency optical and optoelectronic devices. 展开更多
关键词 GGA Cd Elastic and Optoelectronic Properties of KCdF3:ab initio Calculations through LDA/GGA/TB-mBJ within FP-LAPW Method LDA FP
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Quantum Chemical Study of Potential Energy Surface in the Formation of Atmospheric Sulfuric Acid
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作者 Emily L.Tao Jessica Y.Li +1 位作者 Samantha Soriano Fu-Ming Tao 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2018年第4期503-509,615,共8页
A new potential energy surface (PES) for the atmospheric formation of sulfuric acid from OH+SO2 is investigated using density functional theory and high-level ab initio molecular orbital theory. A pathway focused o... A new potential energy surface (PES) for the atmospheric formation of sulfuric acid from OH+SO2 is investigated using density functional theory and high-level ab initio molecular orbital theory. A pathway focused on the new PES assumes the reaction to take place between the radical complex SO3.HO2 and H2O. The unusual stability of SO3.HO2 is the principal basis of the new pathway, which has the same final outcome as the current reaction mechanism in the literature but it avoids the production and complete release of SO3. The entire reaction pathway is composed of three consecutive elementary steps: (1) HOSO2+O2-+SO3.HO2, (2) SO3.HO2+H20-+SO3·H2O·HO2, (3) SO3.H20.HO2-+H2SO4+HO2. All three steps have small energy barriers, under 10 kcal/rnol, and are exotherrnic, and the new pathway is there- fore favorable both kinetically and therrnodynarnically. As a key step of the reactions, step (3), HO2 serves as a bridge molecule for low-barrier hydrogen transfer in the hydrolysis of SO3. Two significant atmospheric implications are expected frorn the present study. First, SO3 is not released from the oxidation of SO2 by OH radical in the atmosphere. Second, the conversion of SO2 into sulfuric acid is weakly dependent on the humidity of air. 展开更多
关键词 Quantum chernistry Atmospheric chernistry Sulfur dioxide Sulfuric acid Computational chernistry Density functional theory ab initio methods
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Investigation of the topological shape of bovine serum albumin in solution by small-angle x-ray scattering at Beijing synchrotron radiation facility
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作者 董淑强 李丽琴 +2 位作者 刘鹏 董宇辉 陈熙萌 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第12期4574-4579,共6页
This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radia- tion Facility, the topological shape of ligand-free bovine serum albumin in solution has been investiga... This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radia- tion Facility, the topological shape of ligand-free bovine serum albumin in solution has been investigated. An appropriate scattering curve is obtained and the calculated value of the gyration radius is 31.2~=t=0.25 ~_ (11=0.1 nm) which is co- incident with other ones' results. It finds that the low-resolution structure models obtained by making use of ab initio reconstruction methods are fitting the crystal structure of human serum albumin very well. All of these results perform the potential of the beamline to apply to structural biology studies. The characteristics, the defects, and the improving measures of the station in future are also discussed. 展开更多
关键词 small-angle x-ray scattering ab initio methods bovine serum albumin Beijing synchrotron radiation facility
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An investigation of ab initio shell-model interactions derived by no-core shell model
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作者 XiaoBao Wang GuoXiang Dong +2 位作者 QingFeng Li CaiWan Shen ShaoYing Yu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第9期52-58,共7页
The microscopic shell-model effective interactions are mainly based on the many-body perturbation theory (MBPT), the first work of which can be traced to Brown and Kuo's first attempt in 1966, derived from the Hama... The microscopic shell-model effective interactions are mainly based on the many-body perturbation theory (MBPT), the first work of which can be traced to Brown and Kuo's first attempt in 1966, derived from the Hamada-Johnstou nucleon-nucleon potential. However, the convergence of the MBPT is still unclear. On the other hand, ab initio theories, such as Green's function Monte Carlo (GFMC), no-core shell model (NCSM), and coupled-cluster theory with single and double excitations (CCSD), have made many progress in recent years. However, due to the increasing demanding of computing resources, these ab initio applications are usually limited to nuclei with mass up to A = 16. Recently, people have realized the ab initio construction of valence-space effective interactions, which is obtained through a second-time renormalization, or to be more exactly, projecting the full-many- body Hamiltonian into core, one-body, and two-body cluster parts. In this paper, we present the investigation of such ab initio shell-model interactions, by the recent derived sd-shell effective interactions based on effective J-matrix Inverse Scattering Potential (JISP) and chiral effective-field theory (EFT) through NCSM. In this work, we have seen the similarity between the ab initio shell- model interactions and the interactions obtained by MBPT or by empirical fitting. Without the inclusion of three-body (3-bd) force, the ab initio shell-model interactions still share similar defects with the microscopic interactions by MBPT, i.e., T = 1 channel is more attractive while T = 0 channel is more repulsive than empirical interactions. The progress to include more many-body correlations and 3-bd force is still badly needed, to see whether such efforts of ab initio shell-model interactions can reach similar precision as the interactions fitted to experimental data. 展开更多
关键词 shell model effective interactions ab initio methods
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Ab initio study on the mechanism of rhodium-complex-catalyzed carbonylation of methanol to acetic acid 被引量:3
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作者 雷鸣 冯文林 +2 位作者 郝茂荣 冀永强 徐振锋 《Science China Chemistry》 SCIE EI CAS 2001年第5期465-472,共8页
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 optim... 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. 展开更多
关键词 rhodium complex CARBONYLATION ab initio method effective core potential
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Density functional theory (DFT) and ab initio investigations of the electronic and molecular structures of the monomer and the dimer of trimethylaluminium
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作者 洪功义 曹晓燕 +2 位作者 王殿勋 黎乐民 徐光宪 《Chinese Journal of Chemistry》 SCIE CAS CSCD 1998年第3期209-212,共4页
The electronic and molecular structures of the monomer and dimer of trimethylaluminium have been studied using density functional theory and ab initio MP2 method. The optimized geometry of the monomer Al(CH3)3 is of C... The electronic and molecular structures of the monomer and dimer of trimethylaluminium have been studied using density functional theory and ab initio MP2 method. The optimized geometry of the monomer Al(CH3)3 is of C3h symmetry, whew that of the dimer [Al(CH3)3]2 contains a carbon-bridged four-membered ring structure with C2h symmetry. The hydrogen-bridged six-membered ring structure is found to be unstable. The calculated dimerization energy for the four-membered ring structure is 78 kJ/mol, in close proximity to the experimental due of 85.27 kJ/mol. 展开更多
关键词 TRIMETHYLALUMINIUM Density Functional Theory (DFT) ab initio methods
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Synthesis,Crystal Structure and Quantum Chemistry of Dibutyltin 3,4-Dimethoxybenzotate Compound 被引量:2
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作者 张复兴 王剑秋 +4 位作者 邝代治 冯泳兰 许志锋 张志坚 张可 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2010年第10期1529-1535,共7页
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... 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. 展开更多
关键词 DIBUTYLTIN 3 4-dimethoxybenzoic acid SYNTHESIS crystal structure ab initio method
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Structure and bonding properties of Y doped Σ37 grain boundary in alumina
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作者 王亚斌 张刚 +2 位作者 刘明杰 陈湘陇 陈军 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第3期1181-1187,共7页
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... 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. 展开更多
关键词 grain boundary ALUMINA Y doping ab initio method
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Synthesis,Crystal Structure and Quantum Chemistry of a Hydration Dibenzyltin Dichloride
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作者 王剑秋 张复兴 +3 位作者 邝代治 冯泳兰 张志坚 许志锋 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第5期597-601,共5页
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... 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. 展开更多
关键词 dibenzyltin dichloride HYDRATION SYNTHESIS crystal structure ab initio method
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The Electronic Structures of Dimeric Diboroxane and Aldiminoborane
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《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1995年第3期232-237,共6页
e have studied the electronic structures of dimeric diboroxane and aldiminob-orane by nieans of STO-3G .ib iuitio SCF method. The energies and the componentanalysis of niolecular orbitals near to frontier orbital hav... e have studied the electronic structures of dimeric diboroxane and aldiminob-orane by nieans of STO-3G .ib iuitio SCF method. The energies and the componentanalysis of niolecular orbitals near to frontier orbital have been given. By bothKoopman' s theoreni and △E_(scf)mietliod we have calculated the ionization potentialsof 8 higlier occupied orbitals and discussed the electron relaxation effect on IP' s cal-culations and the charge distribuuons for the two molecules. 展开更多
关键词 Diboroxane Aldiniuioborane ab initio SCF method
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A Theoretical Study on the Hydrogen-bonded Dimers of HNCO Molecules
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作者 Wang Yan Feng Wen-Lin +1 位作者 Zhang Shao-Wen Zhu Wei-Xin(Chemistry Department, Beijing Normal University, Beijing 100875) 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 1994年第4期312-315,共4页
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 li... 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. 展开更多
关键词 HNCO HYDROGEN-BOND ab initio method
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A charge-conserving approximation——method for ab initio calculations
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作者 DING Fu-Jiang ZHANG Liang-Fu LI Guang-Nian 《Acta Chimica Sinica English Edition》 SCIE CAS CSCD 1989年第4期311-316,共1页
A new method is presented for approximate ab initio calculations in quantum chemistry. It is called CCAM (charge conserving approximation method). The calculation method does not include the use of empirical parameter... A new method is presented for approximate ab initio calculations in quantum chemistry. It is called CCAM (charge conserving approximation method). The calculation method does not include the use of empirical parameters. We use Slater type orbitals as basis set, replacing STO's by STO-2G functions to evaluate three- and four-center integrals and making the STO-2G two- orbital charge distributions have the same total charge as STO. The results are presented for test calculations on five molecules. In view of these results, CCAM is better than ab initio calculations over STO-6G in the results on total energies, kinetic energies and occupied orbital energies. In atomic populations, dipole moments and unoccupied orbital energies, CCAM is also satisfactory. We estimate that CCAM would be as fast as ab initio calculations over STO-2G in evaluating molecular integrals. 展开更多
关键词 STO A charge-conserving approximation ab CCAM method for ab initio calculations
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Ab initio artificial intelligence:Future research of Materials Genome Initiative
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作者 He Li Yong Xu Wenhui Duan 《Materials Genome Engineering Advances》 2023年第2期25-30,共6页
The marriage of artificial intelligence(AI)and Materials Genome Initiative(MGI)could profoundly change the landscape of modern materials research,leading to a new paradigm of data-driven and AI-driven materials discov... The marriage of artificial intelligence(AI)and Materials Genome Initiative(MGI)could profoundly change the landscape of modern materials research,leading to a new paradigm of data-driven and AI-driven materials discovery.In this perspective,we will give an overview on the central role of AI in the MGI research.In particular,an emerging research field of ab initio AI,which applies state-of-the-art AI techniques to help solve bottleneck problems of ab initio computation,will be introduced.The development of ab initio AI will greatly accelerate highthroughput computation,promote the construction of large materials database,and open new opportunities for future research of MGI. 展开更多
关键词 ab initio methods artificial intelligence Materials Genome Initiative
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Effect of tensor correlations on the depletion of nuclear Fermi sea within the extended BHF approach
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作者 尹鹏 董建敏 左维 《Chinese Physics C》 SCIE CAS CSCD 2017年第11期77-82,共6页
We have investigated the effect of tensor correlations on the depletion of the nuclear Fermi sea in symmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach by adopting the AV 18 t... We have investigated the effect of tensor correlations on the depletion of the nuclear Fermi sea in symmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach by adopting the AV 18 two-body interaction and a microscopic three-body force.The contributions from various partial wave channels including the isospin-singlet T = 0 channel,the isospin-triplet T = 1 channel and the T = 0 tensor 3SD1 channel have been calculated.The T =0 neutron-proton correlations play a dominant role in causing the depletion of nuclear Fermi sea.The T =0 correlation-induced depletion turns out to stem almost completely from the 3SD1 tensor channel.The isospin-singlet T = 0 3SD1 tensor correlations are shown to be responsible for most of the depletion,which amounts to more than 70 percent of the total depletion in the density region considered.The three-body force turns out to lead to an enhancement of the depletion at high densities well above the empirical saturation density and its effect increases as a function of density. 展开更多
关键词 ab initio methods nuclear matter three-nucleon forces forces in hadronic systems and effective interactions
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First-principles calculations of elasticity of minerals at high temperature and pressure 被引量:4
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作者 WU ZhongQing WANG WenZhong 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第6期1107-1137,共31页
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... 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 suggest the spin crossover of iron in the lower mantle. The theoretical investigations for the elasticity of minerals at the upper mantle and water effect on elasticity of minerals at the mantle transition zone and subducting slab have also been con- ducted extensively. These researches are critical for understanding better the composition of the upper mantle and water dis- tribution and transport in the Earth's mantle. Most of these were static calculations, which did not include the vibrational (temperature) effect on elasticity, although temperature effect on elasticity is basic because of high temperature at the Earth's interior and huge temperature difference between the ambient mantle and the subducting slab. Including temperature effect on elasticity of minerals should be important future work. New method developed is helpful for these directions. The elasticity of iron and iron-alloy with various light elements has also been calculated extensively. However, more work is necessary in order to meet the demand for constraining the types and amount of light elements at the Earth's core. Keywords Mantle temperature, Mantle composition, Composition of Earth's core, Ab initio method 展开更多
关键词 Mantle temperature Mantle composition Composition of Earth's core ab initio method
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