scholarly journals Электронные состояния наноструктурированных систем: титан и диоксид циркония

2018 ◽  
Vol 60 (10) ◽  
pp. 1861
Author(s):  
В.Г. Заводинский
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Electronic States ◽  
Functional Method ◽  
Density Of Electronic States ◽  
Nanostructured Systems ◽  
Ionic Bonds

AbstractThe density functional method with pseudopotentials are used to study the electron states of nanoparticles and nanostructured systems: chains, films, and three-dimensional nanosystems of titanium and zirconia. It is shown that all studied titanium nanosystems have the density of electronic states (DES) of the metallic type, but zirconia nanosystem demonstrates a dielectric energy gap in the vicinity of the Fermi level. The density of states of nanostructured titanium is close in shape to DES of the single crystal but has a smoother shape due to disordering of the atomic arrangement. The forbidden band width of the nanostructured zirconia is smaller as compared to the corresponding width in crystalline ZrO_2, supposedly because of incomplete saturation of ionic bonds.

scholarly journals Hydrolysis Mechanism of Bismuth in Chlorine Salt System Calculated by Density Functional Method

2020 ◽  
Vol 71 (6) ◽  
pp. 178-193
Author(s):  
Liao Chunfa ◽  
Xu Zhenxin ◽  
Zou Jianbai ◽  
Jiang Pinguoo
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Energy Gap ◽  
Density Functional Method ◽  
Covalent Bond ◽  
Salt System ◽  
Hydroxyl Group ◽  
Partial Density ◽  
Hydroxyl Groups ◽  
Total Density

Based on the density functional theory, this paper presents the calculated cellular electronic properties of BiCl3, BiOCl and Bi3O4Cl, including unit cell energy, band structure, total density of states, partial density of states, Mulliken population, overlapping population, etc. Combined with the thermodynamic analysis of Bi3+ hydrolysis process in chlorine salt system, the conversion mechanism of oxychloride bond in BiCl3 to form BiOCl and Bi3O4Cl by hydrolysis, ethanololysis and ethylene glycol alcohololysis was obtained by infrared spectroscopy. The results indicate that the energy of Bi3O4Cl cell system was lower than that of BiOCl cell, indicating that the structure of Bi3O4Cl was more stable. From the analysis of bond fluctuation, the electron nonlocality in BiOCl belt was relatively large, and the orbital expansibility was strong; thus the structure of BiOCl was relatively active. The state density map of Bi3O4Cl had the widest energy gap, i.e., the covalent bond between Bi3O4Cl was stronger than BiOCl. Therefore, the hydrolysis of BiCl3 would preferentially generate Bi3O4Cl with a more stable structure. The number of charge arrangement, overlapping population and infrared spectrogram indicate that there were two basic ways in the hydrolysis and alcoholysis of BiCl3. Firstly, two chlorine atoms in BiCl3 were replaced by hydroxyl groups ionized by water and alcohol to form [Bi(OH)2Cl] monomer, and BiOCl and Bi3O4Cl were formed by intra-molecular dehydration or inter-molecular dehydration. The other way was that the Bi atom directly reacted with the OH ionized by water and alcohol to form the [Bi-OH] monomer, and the Cl atom replaced the H atom on the hydroxyl group in the [Bi-OH] monomer to further form BiOCl and Bi3O4Cl.

Description of Substitutional Adsorption of Magnetic Ions on Metallic Surfaces with Formation of Monolayer Ferromagnetic Films Using the Spin-Density Functional Method

2012 ◽  
Vol 190 ◽  
pp. 27-30 ◽  
Author(s):  
S.P. Klimov ◽  
M.V. Mamonova ◽  
Vladimir V. Prudnikov
Keyword(s):  
Spin Density ◽  
Density Functional ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Magnetic Ordering ◽  
Transition Metal Ions ◽  
Functional Method ◽  
Magnetic Characteristics ◽  
Metallic Surfaces ◽  
Ferromagnetic Ordering

At present time, a large number of experimental works have been devoted to the study of magnetic ordering in Fe, Co, and Ni ultrathin films [. The investigation of a nature of magnetism in these structures has a large fundamental interest through an observable dimensionality crossover of magnetic characteristics from three dimensional values for films with thickness d 10 nm to two dimensional values for films with thickness d 1-2 nm. It has been established that the long-range ferromagnetic order arises in films at some effective film thickness. However, the nature and regularities of this phenomenon remain not quite clear. In our paper [ it was developed in terms of the spin-density functional theory the description of influence of the temperature and ferromagnetic ordering on the adsorption of Fe, Co, and Ni transition metal ions on a nonmagnetic substrate with the formation of a submonolayer films. For case of nonactivated adsorption the conditions for the formation of magnetic monoatomic films stable with respect to island adsorption with a change in the coverage parameter θ are revealed. It was demonstrated that the inclusion of the ferromagnetic ordering substantially affects the adsorption energy and leads to its considerable increase.

Anion-Cation Replacement Effect on the Structural and Optoelectronic Properties of the LiMX2 (M = Al, Ga, In; X = S, Se, Te) Compounds: A First Principles Study

2018 ◽  
Vol 73 (7) ◽  
pp. 645-655 ◽  
Author(s):  
Amjad Khan ◽  
M. Sajjad ◽  
G. Murtaza ◽  
A. Laref
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Density Functional Method ◽  
Covalent Bond ◽  
Functional Method ◽  
Generalized Gradient ◽  
Lattice Constants ◽  
Crystal Unit Cell ◽  
Ionic Bonds ◽  
Structural And Optoelectronic Properties

AbstractIn the chalcopyrite (or tetragonal) phase, different physical properties of the ternary LiMX2 (M = Al, Ga, In and X = S, Se, Te) compounds are studied by the very accurate density functional method. The optimized lattice constants and the bandgaps are close to the existing experimental data. In addition, for most of the LiMX2 compounds, when the cations change from Al to In and anions from S to Te, the lattice constant and equilibrium volume for the crystal unit cell increase whereas the bulk modulus decreases. Using different generalized gradient approximations, the band structure calculations are performed. Generally, it was observed that there exists a decreasing tendency of the bandgap energies except for the LiAlSe2, LiInSe2, and LiGaTe2 compounds due to the change from Al to In as well as the change from S to Te. The bonding analysis shows that ionic bonds are present between the Li-X atoms, while a covalent bond exists between the M cations and X anions. The optical properties of the compounds are studied by calculating the real and imaginary components of the refractive index, reflectivity, optical conductivity, and birefringence. In addition, the optical properties from the calculations show that these materials are appropriate applicants to be utilized as Bragg’s reflector or applied in optoelectronic and solar cell technology.

scholarly journals Signature-dependent triaxiality for shape evolution from superdeformation in rapidly rotating 40Ca and 41Ca

2020 ◽  
Vol 2020 (6) ◽  
Author(s):  
Shinkuro Sakai ◽  
Kenichi Yoshida ◽  
Masayuki Matsuo
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Decisive Role ◽  
Functional Method ◽  
Space Representation ◽  
Coordinate Space ◽  
Shape Evolution ◽  
Energy Density Functional ◽  
Collective Rotation

Abstract We investigate the possible occurrence of highly elongated shapes near the yrast line in $^{40}$Ca and $^{41}$Ca at high spins on the basis of the nuclear energy-density functional method. Both the superdeformed (SD) yrast configuration and the yrare configurations on top of the SD band are described by solving the cranked Skyme–Kohn–Sham equation in the three-dimensional coordinate space representation. It is suggested that some of the excited SD bands undergo band crossings and develop to hyperdeformation (HD) beyond $J \simeq 25 \hbar$ in $^{40}$Ca. We find that the change of triaxiality in response to rotation plays a decisive role in the shape evolution towards HD, and that this is governed by the signature quantum number of the last occupied orbital at low spins. This mechanism can be verified in an experimental observation of the positive-parity SD yrast signature-partner bands in $^{41}$Ca, one of which ($\alpha=+1/2$) undergoes crossings with the HD band, while the other ($\alpha=-1/2$) shows smooth evolution from collective rotation at low spins to non-collective rotation with an oblate shape at termination.

Computer Simulation of an Synthetic Ultraviolet Absorbent in the Interface of DMB and DMF

2010 ◽  
Vol 146-147 ◽  
pp. 966-971
Author(s):  
Qi Hua Jiang ◽  
Hai Dong Zhang ◽  
Bin Xiang ◽  
Hai Yun He ◽  
Ping Deng
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Density Functional ◽  
Density Functional Method ◽  
Mean Field ◽  
Functional Method ◽  
Dynamic Density ◽  
Interface Phase ◽  
Simulation Results

This work studies the aggregation of an synthetic ultraviolet absorbent, named 2-hydroxy-4-perfluoroheptanoate-benzophenone (HPFHBP), in the interface between two solvents which can not completely dissolve each other. The aggregation is studied by computer simulations based on a dynamic density functional method and mean-field interactions, which are implemented in the MesoDyn module and Blend module of Material Studios. The simulation results show that the synthetic ultraviolet absorbent diffuse to the interface phase and the concentration in the interface phase is greater than it in the solvents phase.

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