FIRST-PRINCIPLES STUDY OF ADSORPTION OF CN ON Cu(111)

2007 ◽  
Vol 06 (03) ◽  
pp. 523-529 ◽  
Author(s):  
WENZHEN LAI ◽  
HONG RAN ◽  
DAIQIAN XIE
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Stationary Points ◽  
Plane Wave Expansion ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Parallel Mode ◽  
Pseudo Potential

The adsorption of CN on Cu (111) has been investigated using density functional theory calculations based on plane-wave expansion and pseudo-potential treatment. Calculations within the generalized gradient approximation predicted a preference for CN in the fcc C -down site. No stationary points corresponding to pure parallel mode were found. But the tilted mode was found to be achievable. The calculated vibrational frequencies of CN were used to correctly discriminate between the adsorption sites.

scholarly journals First-Principles Calculations of the Electronic Structure and Optical Properties of Yttrium-Doped ZnO Monolayer with Vacancy

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 724
Author(s):  
Qian Wu ◽  
Ping Wang ◽  
Yan Liu ◽  
Han Yang ◽  
Jingsi Cheng ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Light Region ◽  
Application Potential ◽  
Doped Zno

The electronic structures and optical characteristics of yttrium (Y)-doped ZnO monolayers (MLs) with vacancy (zinc vacancy, oxygen vacancy) were investigated by the first-principles density functional theory. Calculations were performed with the GGA+U (generalized gradient approximation plus U) approach, which can accurately estimate the energy of strong correlation semiconductors. The results show that the formation energy values of Y-doped ZnO MLs with zinc or oxygen vacancy (VZn, VO) are positive, implying that the systems are unstable. The bandgap of Y-VZn-ZnO was 3.23 eV, whereas that of Y-VO-ZnO was 2.24 eV, which are smaller than the bandgaps of pure ZnO ML and Y-doped ZnO MLs with or without VO. Impurity levels appeared in the forbidden band of ZnO MLs with Y and vacancy. Furthermore, Y-VZn-ZnO will result in a red-shift of the absorption edge. Compared with the pure ZnO ML, ZnO MLs with one defect (Y, VZn or VO), and Y-VZn-ZnO, the absorption coefficient of Y-VO-ZnO was significantly enhanced in the visible light region. These findings demonstrate that Y-VO-ZnO would have great application potential in photocatalysis.

ADSORPTION AND DISSOCIATION OF O2 ON Ti3Al (0001) STUDIED BY FIRST-PRINCIPLES

2015 ◽  
Vol 22 (04) ◽  
pp. 1550053 ◽  
Author(s):  
LI-JING WEI ◽  
JIAN-XIN GUO ◽  
XIU-HONG DAI ◽  
YING-LONG WANG ◽  
BAO-TING LIU
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Structure Optimization ◽  
Oxygen Molecule ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Adsorption Sites ◽  
Generalized Gradient Approximation ◽  
Junction Site ◽  
Adsorption And Dissociation

The adsorption and dissociation of oxygen molecule on Ti 3 Al (0001) surface have been investigated by density functional theory (DFT) with the generalized gradient approximation (GGA). All possible adsorption sites including nine vertical and fifteen parallel sites of O 2 are considered on Ti 3 Al (0001) surface. It is found that all oxygen molecules dissociate except for three vertical adsorption sites after structure optimization. This indicates that oxygen molecules prefer to dissociate on the junction site between Ti and Al atoms. Oxygen atoms coming from dissociation of oxygen molecule tend to occupy the most stable adsorption sites of the Ti 3 Al (0001) surface. The distance of O – O is related to the surface dissociation distance of Ti 3 Al (0001) surface. The valence electron localization function (ELF) and projected density of states (DOS) show that the bonds of O – O are breakaway at parallel adsorption end structures.

Electronic Structure and Optical Properties of InN: A First-Principles Study

2013 ◽  
Vol 760-762 ◽  
pp. 425-428
Author(s):  
Wei Hua Wang ◽  
Guo Zhong Zhao
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Potential Method ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Density ◽  
Pseudo Potential

The electronic properties and the optical properties of wurtzite InN are studied by the first-principles calculations based on the density functional theory. The calculations are based on the Generalized-Gradient Approximation (GGA) and implemented in Plane Wave Self-Consist Field (PWSCF). The optical properties of InN are investigated by the pseudo-potential method with PBEsol-GGA within the WIEN2K program. Band structure, density of states and dielectric functions are calculated detailedly. The energy transitions are observed and compared existing data at critical points. Moreover the new peak in between the region 12 eV to 14 eV should be due to transitions from the In-5p states to the N-2s states.

First-Principles Study of Electronic and Optical Properties in Wurtzite ZnCoO Alloys

2013 ◽  
Vol 333-335 ◽  
pp. 1847-1852
Author(s):  
Ming Zhu Li ◽  
Li Mei Song ◽  
Shan Wang
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Optical Constants ◽  
Density Functional Theory Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
The Density Functional Theory ◽  
Co Concentration

We perform a first-principles simulation to research the electronic and optical properties of wurtzite Zn1-xCoxO. The simulations are based on the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. Calculations are carried out in different concentrations. With increasing Co concentration, the band gap of Zn1-xCoxO decreases due to the shift of valence band. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Meanwhile, the optical constants of pure ZnO and ZnCoO alloys such as loss function, refractive index and reflectivity, are discussed.

scholarly journals Structural, Mechanical and Thermodynamic Properties under Pressure Effect of Rubidium Telluride: First Principle Calculations

2017 ◽  
Vol 62 (2) ◽  
pp. 865-871 ◽  
Author(s):  
K. Bidai ◽  
M. Ameri ◽  
I. Ameri ◽  
D. Bensaid ◽  
A. Slamani ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
Poisson Ratio ◽  
Density Functional Theory Calculations ◽  
Lattice Parameter ◽  
Thermodynamic Quantities ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Equilibrium Lattice Parameter

AbstractFirst-principles density functional theory calculations have been performed to investigate the structural, elastic and thermodynamic properties of rubidium telluride in cubic anti-fluorite (anti-CaF2-type) structure. The calculated ground-state properties of Rb2Te compound such as equilibrium lattice parameter and bulk moduli are investigated by generalized gradient approximation (GGA-PBE) that are based on the optimization of total energy. The elastic constants, Young’s and shear modulus, Poisson ratio, have also been calculated. Our results are in reasonable agreement with the available theoretical and experimental data. The pressure dependence of elastic constant and thermodynamic quantities under high pressure are also calculated and discussed.

Understanding the advantage of hexagonal WO3 as an efficient photoanode for solar water splitting: a first-principles perspective

2016 ◽  
Vol 4 (29) ◽  
pp. 11498-11506 ◽  
Author(s):  
Taehun Lee ◽  
Yonghyuk Lee ◽  
Woosun Jang ◽  
Aloysius Soon
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Water Splitting ◽  
Anode Material ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Good Alternative ◽  
Functional Theory ◽  
Solar Water Splitting

Using first-principles density-functional theory calculations, we investigate the advantage of using h-WO3 (and its surfaces) over the larger band gap γ-WO3 phase for the anode in water splitting. We demonstrate that h-WO3 is a good alternative anode material for optimal water splitting efficiencies.

Probing the electronic structures of Con (n = 1–5) clusters on γ-Al2O3 surfaces using first-principles calculations

2017 ◽  
Vol 19 (5) ◽  
pp. 3679-3687 ◽  
Author(s):  
Tao Yang ◽  
Masahiro Ehara
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
First Principles Calculations ◽  
Functional Theory

Using density functional theory calculations, we discussed the geometric and electronic structures and nucleation of small Co clusters on γ-Al2O3(100) and γ-Al2O3(110) surfaces.

Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

2006 ◽  
Vol 84 (2) ◽  
pp. 115-120 ◽  
Author(s):  
G Y Gao ◽  
K L Yao ◽  
Z L Liu
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Pseudopotential Calculations ◽  
Correlation Potential ◽  
Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

Preliminary First Principles Study Of Hf and Zr Aluminates as Replacement High-k Dielectrics

2001 ◽  
Vol 670 ◽  
Author(s):  
Michael Haverty ◽  
Atsushi Kawamoto ◽  
Gyuchang Jun ◽  
Kyeongjae Cho ◽  
Robert Dutton
Keyword(s):  
Density Functional Theory ◽  
Dielectric Constant ◽  
Bulk Density ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Conduction Band Edge ◽  
Functional Theory ◽  
Trade Off ◽  
High K

ABSTRACTBulk Density Functional Theory calculations were performed on Hf and Zr substitutions for Al in κ-alumina. The lowest energy configuration found was an octahedrally coordinated Zr site. Zr dissolution was favorable with an enthalpy of -2eV/unit cell for forming Al1.875Zr0.125O3 from pure Zr and κ-alumina. Hf and Zr substitution for Al atoms introduced empty d-states below the conduction band edge reducing the Eg of pure κ-alumina (7.5eV) to 6.4-5.9eV. The edge of the valence band however remained fixed by the O p-state character. The substitution of Hf and Zr into the alumina structure may lead to a higher dielectric constant, but will also reduce Eg and result in a trade off in tunneling currents in devices.

Sign in / Sign up

Export Citation Format

Share Document