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Ethylene Adsorption on Ag(111), Rh(111) and Ir(111) by(meta)-GGA based Density Functional theory Calculations

Chinese Journal of Chemical Physics 2019年第4期32卷 437-443,I0002页

作者： Pei-pei Chen Bing-yan Zhang Xiang-kui Gu Wei-xue Li State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Department of Chemical Engineering and Materials Science Wayne State University Detroit MI 48202 USA Department of Chemical Physics College of Chemistry and Materials Science University of Science and Technology of China Hefei National Laboratory for Physical Sciences at the Microscale Hefei 230026 China University of Chinese Academy of Sciences Beijing 100049 China

Accurate description of the adsorption process of reactants on metal surfaces from theory is crucial for mechanistic understanding of activity and selectivity of metal catalysts, but it remains challengeable for the nowadays first-principles theory due to the lack of proper exchange-correlation functional describing the distinct interactions involved. We studied here the potential energy surfaces of ethylene adsorption on Ag(111), Rh(111) and Ir(111) using density functional theory calculations and (meta)-GGA functional including PBE, BEEF-vdW, SCAN, and SCAN+rVV10. For ethylene adsorption on noble metal Ag(111), it is found that BEEF-vdW, SCAN and SCAN+rVV10 predict the presence of the physisorption states only. For Rh(111), both SCAN and SCAN+rVV10 find that there is a precursor physisorption state before the chemisorption state. In contrast, there is no precursor state found based on potential energy surfaces from BEEF-vdW and PBE. Whereas for Ir(111), BEEF-vdW predicts the existence of a rather shallow precursor physisorption state, in addition to the chemisorption state. Irrespective to the transition metals considered, we find that SCAN+rVV10 gives the strongest binding strength, followed by SCAN, and PBE/BEEF-vdW, accordingly. The present work highlights great dependence of potential energy surface of ethylene adsorption on transition metal surfaces and exchange-correlation functionals.

关键词： Ethylene adsorption Potential energy curve Transition metal surface Exchange-correlation functionals first-principles theory

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Theoretical investigation on the solution behaviors of Ba and Zr in uranium dinitride

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Science China Chemistry 2015年第12期58卷 1891-1897页

作者： Yujuan Zhang Jianhui Lan Qunyan Wu Congzhi Wang Tao Bo Zhifang Chai Weiqun Shi Key Laboratory of Nuclear Radiation and Nuclear Energy Technology

The in-pile performance of ceramic fuels is significantly affected by the fission products. In this work, we have performed first-principles density functional theoretical calculations to study the interaction between metallic fission products(barium and zirconium) and the uranium dinitride UN2 matrix. The thermodynamic properties and bonding nature of Ba and Zr atoms in different incorporation configurations indicate that Zr is more soluble in UN2 matrix than Ba. With increasing the concentration of the impurity atoms, Zr-doped UN2 exhibits a slight tendency to contract, while Ba-doped UN2 tends to swell. Based on the competition between steric effect and chemical interaction, various incorporation trends for Ba and Zr in UN2 as well as in UN have been understood.

关键词： uranium dinitride first-principles theory thermodynamic property bonding nature

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first-principles calculations of structure and elasticity of hydrous fayalite under high pressure

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Chinese Physics B 2017年第12期26卷 389-396页

作者：张传瑜王绪本赵晓凤陈星润虞游田晓峰 College of Geophysics Chengdu University of Technology Chengdu 610059 China College of Optoelectronic Technology Chengdu University of Information Technology Chengdu 610225 China College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu 610059 China

The structures, elasticities, sound velocities, and electronic properties of anhydrous and hydrous fayalite （Fe2SiO4 and Fe1.75H0.5SiO4） under high pressure have been investigated by means of the density functional theory within the generalized gradient approximation （GGA） with the on-site Coulomb energy being taken into account （GGA＋U）. The optimized results show that H atoms prefer to substitute Fe atoms in the Fe1 site. Compared with the anhydrous fayalite Fe2SiO4, the mass density, elastic moduli, and sound velocities of Fe1.75H0.5SiO4 slightly decrease. According to our data, adding 2.3 wt% water into fayalite leads to reductions of compressional and shear wave velocities （VP and VS） by 3.4%-7.5% and 0.3%-3.4% at pressures from 0 GPa to 25 GPa, respectively, which are basically in agreement with the 2%-5% reductions of sound velocity obtained by the experimental measurement in the low velocity zones （LVZ）. Based on the electronic structure, the valence and conduction bands are slightly broader for hydrous fayalite. However, hydrous fayalite keeps the insulation characteristics under the pressures up to 30 GPa, which indicates that hydration has little effect on its electronic structure.

关键词： hydrous fayalite first-principles theory crystal structure elasticity

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Effects of N doping on photoelectric properties of along different directions of ZnO bulk and nanotube

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Chinese Physics B 2014年第12期23卷 339-345页

作者：郑红梅房晓勇蔡丽霞尹爱查金海波于晓霞曹茂盛 School of Science Yanshan University School of Materials Science and Engineering Beijing Institute of Technology

The electronic structures and optical properties of N-doped Zn O bulks and nanotubes are investigated using the firstprinciples density functional method. The calculated results show that the main optical parameters of Zn O bulks are isotropic（especially in the high frequency region）, while Zn O nanotubes exhibit anisotropic optical properties. N doping results show that Zn O bulks and nanotubes present more obvious anisotropies in the low-frequency region. Thereinto, the optical parameters of N-doped Zn O bulks along the [100] direction are greater than those along the [001] direction, while for N-doped nanotubes, the variable quantities of optical parameters along the [100] direction are less than those along the[001] direction. In addition, refractive indexes, electrical conductivities, dielectric constants, and absorption coefficients of Zn O bulks and nanotubes each contain an obvious spectral band in the deep ultraviolet（UV）（100 nm～ 300 nm）. For each of N-doped Zn O bulks and nanotubes, a spectral peak appears in the UV and visible light region, showing that N doping can broaden the application scope of the optical properties of Zn O.

关键词： Zn O NTs N-doped Zn O electronic structure optical properties first-principles theory

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first-principles study of the co-effect of carbon doping and oxygen vacancies in ZnO photocatalyst

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Chinese Physics B 2021年第2期30卷 419-425页

作者： Jia Shi Lei Wang Qiang Gu Department of Physics University of Science and Technology BeijingBeijing 100083China

Although tuning band structure of optoelectronic semiconductor-based materials by means of doping single defect is an important approach for potential photocatalysis application,C-doping or oxygen vacancy(Vo)as a single defect in ZnO still has limitations for photocatalytic ***,the influence of co-existence of various defects in ZnO still lacks sufficient ***,we investigate the photocatalytic properties of ZnOx C0.0625(x=0.9375,0.875,0.8125),confirming that the co-effect of various defects has a greater enhancement for photocatalytic activity driven by visible-light than the single defect in *** clarify the underlying mechanism of co-existence of various defects in ZnO,we perform systematically the electronic properties calculations using density functional *** is found that the coeffect of C-doping and Vo in ZnO can achieve a more controllable band gap than doping solely in ***,the impact of the effective masses of ZnO_(x)C_(0.0625)(x=0.9375,0.875,0.8125)is also taken into *** comparison with heavy Vo concentrations,the light Vo concentration(x=0.875)as the optimal component together with C-doping in ZnO,can significantly improve the visible-light absorption and benefit photocatalytic activity.

关键词： first-principles theory electron density of states and band structure of crystalline solids Ⅲ-ⅤandⅡ-Ⅵsemiconductors

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B_(111),B_(112),_(B113),and B_(114):The most stable core-shell borospherenes with an icosahedral B_(12) core at the center exhibiting superatomic behaviors

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Nano Research 2021年第12期14卷 4719-4724页

作者： Min Zhang Hai-Gang Lu Si-Dian Li Institute of Molecular Science Shanxi UniversityTaiyuan030006China

Boron allotropes are known to be predominately constructed by icosahedral B_(12) cages,while icosahedral-B_(12) stuffing proves to effectively improve the stability of fullerene-like boron nanoclusters in the size range between B_(98)–B_(102).However,the thermodynamically most stable core-shell borospherenes with a B_(12) icosahedron at the center still remains *** on the structural motif of D5h C_(70) and extensive first-principles theory calculations,we predict herein the high-symmetry C5v B111+(3)which satisfies the Wade’s n+1 and n+2 skeletal electron counting rules exactly and the approximately electron sufficient Cs B_(111)(4),Cs B_(112)(5),Cs B_(113)(6),and Cs B_(114)(7)which are the most stable neutral core-shell borospherenes with a B_(12) icosahedron at the center reported to date in the size range between B_(68)–B_(130),with Cs B112(5)being the thermodynamically most favorite species in the *** orbital and bonding analyses indicate that these spherically aromatic species all contain a negatively charged icosahedral B_(122)−core at the center which exhibits typical superatomic behaviors in the electronic configuration of 1S21P61D101F8,with its dangling valences saturated by twelve radial B-B 2c-2eσbonds between the B_(12) inner core and the B_(70) outer *** infrared(IR)and Raman spectra of the concerned species are computationally simulated to facilitate their future characterizations.

关键词： first-principles theory borospherenes structures bonding superatomic behaviors spherical aromaticity

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Nature of the band gap of halide perovskites ABX_3(A=CH_3NH_3,Cs;B=Sn,Pb;X=Cl,Br,I):first-principles calculations

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Chinese Physics B 2015年第11期24卷 358-362页

作者：袁野徐闰徐海涛洪峰徐飞王林军 School of Materials Science and Engineering Shanghai University Department of Physics Shanghai University

The electronic structures of cubic structure of ABX3（A=CH3NH3, Cs; B=Sn, Pb; X=Cl, Br, I） are analyzed by den- sity functional theory using the Perdew-Burke-Ernzerhof exchange-correlation functional and using the Heyd-Scuseria- Ernzerhof hybrid functional. The valence band maximum （VBM） is found to be made up by an antibonding hybridization of B s and X p states, whereas bands made up by the π antibonding of B p and X p states dominates the conduction band minimum （CBM）. The changes of VBM, CBM, and band gap with ion B and X are then systematically summarized. The natural band offsets of ABX3 are partly given. We also found for all the ABX3 perovskite materials in this study, the bandgap increases with an increasing lattice parameter. This phenomenon has good consistency with the experimental results.

关键词： first-principles theory electron density of states band structure of crystalline solids organicinorganic hybrid nanostructures

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Structures and electrical properties of pure and vacancy-included ZnO NWs of different sizes

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Chinese Physics B 2015年第12期24卷 507-511页

作者：于晓霞周彦刘甲金海波房晓勇曹茂盛 School of Science Yanshan University School of Materials Science and Engineering Beijing Institute of Technology

The structures and electronic properties of ZnO nanowires（NWs） of different diameters are investigated by employing the first-principles density functional theory. The results indicate that the oxygen vacancy（VO） exerts a more evident influence on the band gap of the ZnO NWs. However, the effect will be weakened with the increase of the diameter. In addition, the energy band shifts downward due to the existence of VOand the offset decreases with the reduction of the VOconcentration. As the concentration of surface Zn atoms decreases, the conduction band shifts downward, while 2p electrons are lost in the oxygen vacancy, resulting in the split of valence band and the formation of an impurity level. Our findings agree well with the previous observations and will be of great importance for theoretical research based on ZnO NWs.

关键词： ZnO NWs oxygen vacancies lattice structure electronic properties first-principles theory

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Effects of substitution of group-V atoms for carbon or silicon atoms on optical properties of silicon carbide nanotubes

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Chinese Physics B 2021年第6期30卷 602-609页

作者： Ying-Ying Yang Pei Gong Wan-Duo Ma Rui Hao Xiao-Yong Fang Key Laboratory for Microstructural Material Physics of Hebei Province School of ScienceYanshan UniversityQinhuangdao 066004China

Silicon carbide nanotubes(SiCNTs) have broad application prospects in the field of micro-nanodevices due to their excellent physical properties. Based on first-principles, the difference between optical properties of SiCNTs where C atom or Si atom is replaced by group-V element is studied. The results show that the optical absorptions of SiCNTs doped by different elements are significantly different in the band of 600 nm–1500 nm. The differences in photoconductivity, caused by different doping elements, are reflected mainly in the band above 620 nm, the difference in dielectric function and refractive index of SiCNTs are reflected mainly in the band above 500 nm. Further analysis shows that SiCNTs doped with different elements change their band structures, resulting in the differences among their optical properties. The calculation of formation energy shows that SiCNTs are more stable when group-V element replaces Si atom, except N atom. These research results will be beneficial to the applications of SiC nanomaterials in optoelectronic devices and provide a theoretical basis for selecting the SiCNTs' dopants.

关键词： silicon carbide nanotubes group-V doped optical properties first-principles theory

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first principles calculations of alloying element diffusion coefficients in Ni using the five-frequency model

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Chinese Physics B 2012年第10期21卷 585-591页

作者：吴琼李树索马岳宫声凯 School of Materials Science and Engineering Beihang University

The diffusion coefficients of several alloying elements（Al,Mo,Co,Ta,Ru,W,Cr,Re） in Ni are directly calculated using the five-frequency model and the first principles density functional *** correlation factors provided by the five-frequency model are explicitly *** calculated diffusion coefficients show their excellent agreement with the available experimental *** the diffusion pre-factor（D 0） and the activation energy（Q） of impurity diffusion are *** diffusion coefficients above 700 K are sorted in the following order：DAl〉DCr〉DCo〉DTa〉DMo〉DRu〉DW〉D *** is found that there is a positive correlation between the atomic radius of the solute and the jump energy of Ni that results in the rotation of the solute-vacancy pair（E 1）.The value of E 2-E 1（E 2 is the solute diffusion energy） and the correlation factor each also show a positive *** larger atoms in the same series have lower diffusion activation energies and faster diffusion coefficients.

关键词： first-principles theory diffusion coefficients alloying element superalloy activation energy and diffusion pre-factor

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