Adsorption of Ethylenediamine on Cu Surfaces: Attributes of a Successful Capping Molecule Using First-Principles Calculations

Nanoscale ◽  
2021 ◽  
Author(s):  
Zihao Chen ◽  
Kristen A. Fichthorn
Keyword(s):  
First Principles ◽  
Controlled Synthesis ◽  
First Principles Calculations ◽  
Capping Agents ◽  
Wide Range ◽  
Shape Controlled

The shape-controlled synthesis of Cu nanocrystals can benefit a wide range of applications, though challenges exist in achieving high and selective yields to a particular shape. Capping agents play a...

Stability and Structures of Constitutional Defects in Nonstoichiometric Intermetallic Compounds by First-Principles Calculations

2005 ◽  
Vol 475-479 ◽  
pp. 3111-3114
Author(s):  
Masataka Mizuno ◽  
Hideki Araki ◽  
Yasuharu Shirai
Keyword(s):  
Intermetallic Compounds ◽  
First Principles ◽  
Electronic Structures ◽  
Stoichiometric Composition ◽  
Electronic Structure Calculations ◽  
First Principles Calculations ◽  
Compositional Dependence ◽  
Wide Range ◽  
Formation Energies ◽  
Structure Calculations

Some of intermetallic compounds exist in a wide range of concentration around the stoichiometric composition. First-principles electronic structure calculations have been performed for constitutional defects in non-stoichiometric CoAl and CoTi in order to investigate their stabilities and structural relaxations induced by constitutional defects. For the evaluation of stabilities of constitutional defects, the compositional dependence curves both of formation energies and of lattice parameters are obtained by the calculations employing supercells in various sizes. The lattice relaxations around constitutional defects are discussed by analyzing the change in electronic structures induced by constitutional defects.

scholarly journals Shape-controlled synthesis of magnetic Fe3O4 nanoparticles with different iron precursors and capping agents

RSC Advances ◽  
2018 ◽  
Vol 8 (41) ◽  
pp. 22917-22923 ◽  
Author(s):  
Hira Fatima ◽  
Dae-Won Lee ◽  
Hyun Joong Yun ◽  
Kyo-Seon Kim
Keyword(s):  
Magnetic Nanoparticles ◽  
Fe3o4 Nanoparticles ◽  
Controlled Synthesis ◽  
Capping Agents ◽  
Modified Method ◽  
Magnetic Fe3o4 Nanoparticles ◽  
Different Shapes ◽  
Shape Controlled ◽  
Magnetic Fe3o4

This paper describes a modified method to prepare monodisperse Fe3O4 magnetic nanoparticles with different shapes (cube, octahedron, and sphere).

Convenient Molecular Approach of Size and Shape Controlled ZnSe and ZnTe Nanocrystals

2001 ◽  
Vol 635 ◽  
Author(s):  
Young-wook Jun ◽  
Jong-Il Park ◽  
Jinwoo Cheon
Keyword(s):  
Particle Size ◽  
Semiconductor Nanocrystals ◽  
Dimensional Sphere ◽  
Controlled Synthesis ◽  
Molecular Approach ◽  
Molecular Precursors ◽  
Size And Shape ◽  
Wide Range ◽  
One Step ◽  
Shape Controlled

AbstractOur study describes a convenient one-step synthesis of ZnSe and ZnTe nanocrystals (NC) whose sizes and shapes are precisely tuned by varing the growth temperature or stabilizing surfactants. We utilized molecular precursors, bis(phenylselenolate or phenyltellurolato)zinc -N,N,N',N'-tetramethylethylenediamine (TMEDA), which effectively produce 0-dimensional sphere or 1-dimensional nanorods of ZnSe or ZnTe, respectively. Nanocrystals are highly monodispersed and luminescent; the emission wavelength varies over a wide range depending on the particle size. This study constitutes a nice demonstration of direct size and shape controlled synthesis of semiconductor nanocrystals and this method can be extended to the synthesis of nanocrystals of other materials.

scholarly journals First-principles calculations of LiNbO3 optical properties: From far-infrared to ultraviolet

2018 ◽  
Vol 32 (05) ◽  
pp. 1850063 ◽  
Author(s):  
Vladimir Saleev ◽  
Alexandra Shipilova
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Atomic Orbital ◽  
Hybrid Approach ◽  
Far Infrared ◽  
Basis Sets ◽  
Dielectric Tensor ◽  
First Principles Calculations ◽  
Wide Range

We perform first-principles calculations of optical properties for ferroelectric phase of LiNbO3 crystal using density functional theory (DFT) for wide range of wavelengths, from far-infrared (IR) to ultraviolet. We study frequency dependence of complex dielectric tensor and related quantities, such as refractive and reflection indices, absorption coefficients, etc. Our calculation incorporates advantages of numerical approaches based on atomic-orbital all-electron Gaussian-type basis sets, as it is realized in CRYSTAL14 program. We compared predictions obtained in general-gradient approach with PBESOL exchange-correlation functional and in hybrid approach with PBESOL0 functional, and we have found that hybrid PBESOL0 functional is more applicable to describe the wide set of the experimental data.

scholarly journals Coexistence of plastic and partially diffusive phases in a helium-methane compound

2020 ◽  
Vol 7 (10) ◽  
pp. 1540-1547
Author(s):  
Hao Gao ◽  
Cong Liu ◽  
Andreas Hermann ◽  
Richard J Needs ◽  
Chris J Pickard ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Diagram ◽  
First Principles ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
First Principles Calculations ◽  
Helium Atoms ◽  
Wide Range ◽  
Pure Methane ◽  
The Universe

Abstract Helium and methane are major components of giant icy planets and are abundant in the universe. However, helium is the most inert element in the periodic table and methane is one of the most hydrophobic molecules, thus whether they can react with each other is of fundamental importance. Here, our crystal structure searches and first-principles calculations predict that a He3CH4 compound is stable over a wide range of pressures from 55 to 155 GPa and a HeCH4 compound becomes stable around 105 GPa. As nice examples of pure van der Waals crystals, the insertion of helium atoms changes the original packing of pure methane molecules and also largely hinders the polymerization of methane at higher pressures. After analyzing the diffusive properties during the melting of He3CH4 at high pressure and high temperature, in addition to a plastic methane phase, we have discovered an unusual phase which exhibits coexistence of diffusive helium and plastic methane. In addition, the range of the diffusive behavior within the helium-methane phase diagram is found to be much narrower compared to that of previously predicted helium-water compounds. This may be due to the weaker van der Waals interactions between methane molecules compared to those in helium-water compounds, and that the helium-methane compound melts more easily.

scholarly journals The Flexible Lubrication Performance of Graphene Used in Diamond Interface as a Solid Lubricant: First-Principles Calculations

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1784
Author(s):  
Jianjun Wang ◽  
Lin Li ◽  
Wentao Yang ◽  
Meng Li ◽  
Peng Guo ◽  
...  
Keyword(s):  
Diamond Film ◽  
First Principles ◽  
Density Functional ◽  
External Pressure ◽  
Diamond Surface ◽  
Interfacial Friction ◽  
First Principles Calculations ◽  
Diamond Surfaces ◽  
Lubrication Performance ◽  
Wide Range

The interfacial friction performances of graphene covered and hydrogen-terminated diamond surfaces were investigated comparatively by first-principles calculations within density functional theory (DFT). Both systems exhibit similar excellent lubricating effects under small load, but the graphene covered interface presents small friction than that of hydrogenated system for the larger load. The calculated interfacial friction between two sheets of graphene covered diamond surface increases slowly than that of hydrogenated system in a wide range of pressure scale, and the friction difference between the two systems increases with increasing external pressure, indicating that graphene has flexible lubricating properties with high load-carrying capacity. This behavior can be attributed to the large interlayer space and a more uniform interlayer charge distribution of graphene covered diamond interface. Our investigations suggest that graphene is a promising candidate as solid lubricate used in diamond film, and are helpful for the understanding of interfacial friction properties of diamond film.

Adsorption of methanol molecule on graphene: Experimental results and first-principles calculations

2018 ◽  
Vol 32 (09) ◽  
pp. 1850102 ◽  
Author(s):  
X. W. Zhao ◽  
Y. L. Tian ◽  
W. W. Yue ◽  
M. N. Chen ◽  
G. C. Hu ◽  
...  
Keyword(s):  
First Principles ◽  
Adsorption Properties ◽  
Experimental Results ◽  
Methanol Molecule ◽  
First Principles Calculations ◽  
Adsorption System ◽  
Geometrical Structures ◽  
Effective Masses ◽  
Wide Range ◽  
Adsorption Energies

Adsorption properties of methanol molecule on graphene surface are studied both theoretically and experimentally. The adsorption geometrical structures, adsorption energies, band structures, density of states and the effective masses are obtained by means of first-principles calculations. It is found that the electronic characteristics and conductivity of graphene are sensitive to the methanol molecule adsorption. After adsorption of methanol molecule, bandgap appears. With the increasing of the adsorption distance, the bandgap, adsorption energy and effective mass of the adsorption system decreased, hence the resistivity of the system decreases gradually, these results are consistent with the experimental results. All these calculations and experiments indicate that the graphene-based sensors have a wide range of applications in detecting particular molecules.

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