QUANTUM MECHANICAL MODELING OF THE COBALT MONOLAYER BEHAVIOR ON A TIC SURFACE

2020 ◽  
Author(s):  
Антон Александрович Гниденко
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Cobalt Atom ◽  
Binding Energies ◽  
Pseudopotential Method ◽  
Quantum Mechanical ◽  
Mechanical Modeling ◽  
Functional Theory ◽  
The Density Functional Theory

Методами теории функционала плотности и псевдопотенциала исследована адгезия монослоя кобальта с поверхностью TiC(001). Показана необходимость поворота монослоя кобальта относительно подложки для получения достоверных результатов. Рассмотрены две стабильные атомные конфигурации для системы 4TiC/5Co, рассчитаны энергии связи, приходящиеся на один атом кобальта. The adhesion of a cobalt monolayer on the TiC (001) surface is studied using the density functional theory and pseudopotential method. The necessity of cobalt monolayer rotation relative to the substrate to obtain reliable results is shown. Two stable atomic configurations for the 4TiC/5Co system are considered, and the binding energies per cobalt atom are calculated.

Mechanisms of Diffusion and Dissociation of E-Centers in Silicon

2005 ◽  
Vol 237-240 ◽  
pp. 1129-1134
Author(s):  
Mariya G. Ganchenkova ◽  
V.A. Borodin ◽  
Risto M. Nieminen
Keyword(s):  
Density Functional Theory ◽  
Monte Carlo ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Density Functional ◽  
Kinetic Monte Carlo ◽  
Binding Energies ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Charge States

In this paper we discuss possible mechanisms of PV annealing in Si. Our approach includes a combination of density functional theory and lattice kinetic Monte-Carlo (LKMC) simulations. The density functional theory is used to find the binding energies and jump barriers for P-V pair at different separations (from one to three interatomic bonds between complex constituents) and in different charge states. The mobility of the complex is simulated by LKMC with event probabilities calculated based on the energies from ab-initio calculations. .

Density functional theory study on CO adsorption on the PdnAl (n = 1–5) clusters

2018 ◽  
Vol 32 (15) ◽  
pp. 1850187 ◽  
Author(s):  
Zhi Li ◽  
Zhonghao Zhou ◽  
Zhen Zhao ◽  
Qi Wang
Keyword(s):  
Density Functional Theory ◽  
Ground State ◽  
Density Functional ◽  
Co Adsorption ◽  
Binding Energies ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Energy Configurations ◽  
Homo Lumo

The configurations, stability, electronic properties and CO adsorption of the ground state Pd[Formula: see text]Al (n = 1–5) clusters are calculated by the density functional theory (DFT). The results reveal that the lowest-energy configurations of Pd[Formula: see text]Al clusters inherit the geometries of the host Pd[Formula: see text] clusters to a larger extent. The C atom in CO molecule prefers to approach more Pd atoms rather than Al atoms in small Pd[Formula: see text]Al clusters. Pd[Formula: see text]AlCO clusters have higher average binding energies than the corresponding small Pd[Formula: see text]CO clusters except for PdCO. AlCO and Pd3AlCO clusters possess better kinetic stability than their neighbors by the HOMO–LUMO gaps. Except for Pd6 clusters, CO molecule prefers to adsorb on small Pd[Formula: see text] clusters rather than Pd[Formula: see text]Al clusters. Both the Al–Pd bonding in Pd[Formula: see text]Al clusters and C–Pd bonding in Pd[Formula: see text]AlCO clusters have certain covalent characters.

scholarly journals Mechanism of Guaiacol Hydrodeoxygenation on Cu (111): Insights from Density Functional Theory Studies

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 523
Author(s):  
Destiny Konadu ◽  
Caroline Rosemyya Kwawu ◽  
Richard Tia ◽  
Evans Adei ◽  
Nora Henriette de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Reaction Path ◽  
Binding Energies ◽  
Functional Theory ◽  
Thermodynamics And Kinetics ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
The Density Functional Theory ◽  
Rate Limiting

Understanding the mechanism of the catalytic upgrade of bio-oils via the process of hydrodeoxygenation (HDO) is desirable to produce targeted oxygen-deficient bio-fuels. We have used calculations based on the density functional theory to investigate the reaction mechanism of HDO of guaiacol over Cu (111) surface in the presence of H2, leading to the formation of catechol and anisole. Our analysis of the thermodynamics and kinetics involved in the reaction process shows that catechol is produced via direct demethylation, followed by dehydrogenation of –OH and re-hydrogenation of catecholate in a concerted fashion. The de-methylation step is found to be the rate-limiting step for catechol production with a barrier of 1.97 eV. Formation of anisole will also proceed via the direct dehydroxylation of guaiacol followed by hydrogenation. Here, the rate-limiting step is the dehydroxylation step with an energy barrier of 2.07 eV. Thermodynamically, catechol formation is favored while anisole formation is not favored due to the weaker interaction seen between anisole and the Cu (111) surface, where the binding energies of guaiacol, catechol, and anisole are -1.90 eV, −2.18 eV, and −0.72 eV, respectively. The stepwise barriers also show that the Cu (111) surface favors catechol formation over anisole as the rate-limiting barrier is higher for anisole production. For catechol, the overall reaction is downhill, implying that this reaction path is thermodynamically and kinetically preferred and that anisole, if formed, will more easily transform.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

A DFT study of spherands containing five anisyl groups — Highly preorganized to bind the alkali metal

2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Ionic Radius ◽  
Binding Energies ◽  
Cavity Size ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Good Agreement

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

A trinuclear chromium(III) chlorocarbyne

2021 ◽  
Author(s):  
Takashi Kurogi ◽  
Keiichi Irifune ◽  
Takahiro Enoki ◽  
Kazuhiko Takai
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Terminal Alkynes ◽  
Functional Theory ◽  
The Density Functional Theory

Reduction of CCl4 by CrCl2 in THF afforded a trinuclear chromium(III) carbyne [CrCl(thf)2)]3(μ3-CCl)(μ-Cl)3. The chlorocarbyne complex reacted with aldehydes to afford chloroallylic alcohols and terminal alkynes. The density functional theory...

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