scholarly journals Interaction of sulfur with impurities in bcc iron

2021 ◽  
Vol 2103 (1) ◽  
pp. 012071
Author(s):  
A V Verkhovykh ◽  
A A Mirzoev ◽  
Yu K Okishev ◽  
N S Dyuryagina
Keyword(s):  
Density Functional Theory ◽  
Software Package ◽  
Density Functional ◽  
Functional Theory ◽  
The Third ◽  
Bcc Iron ◽  
The Density Functional Theory ◽  
Coordination Spheres ◽  
Strong Repulsion ◽  
Substitutional Impurities

Abstract In this work, the modeling of the sulfur interaction with substitutional impurities (Mn, P) and interstitial (C) has been carried out. All calculations were performed using the density functional theory in the WIEN2k software package. For the first two coordination spheres, there is a strong repulsion between carbon and sulfur, but in the third relative position, a slight attraction arises between the atoms. When sulfur interacts with manganese, attraction occurs only for the first coordination sphere, while the dissolution energy of both manganese and sulfur decreases. In the case of the S-P interaction, the binding energy is negative, and the dissolution energy of both sulfur and phosphorus decreases for all configurations, although the distance between phosphorus and sulfur increases. It can be assumed that the presence of phosphorus leads to the accumulation of sulfur in the material.

scholarly journals Ab initio моделирование энергии растворения и энергии связи водорода с 3sp-, 3d- и 4d-примесями в ОЦК-железе

2021 ◽  
Vol 63 (7) ◽  
pp. 830
Author(s):  
М.С. Ракитин ◽  
А.А. Мирзоев
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Theoretical Description ◽  
Atomic Level ◽  
Functional Theory ◽  
Bcc Iron ◽  
Fundamental Understanding ◽  
Substitutional Impurities ◽  
Hydrogen Dissolution

A fundamental understanding of the localization of H atoms in steel is an important step towards a theoretical description of the mechanisms of hydrogen embrittlement at the atomic level. Ab initio calculations within the framework of density functional theory (DFT) is used to investigate the effect of various substitutional impurities Mg, Al, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo , Pd and Cd on the energy of hydrogen dissolution in the lattice of bcc iron. The electronic and elastic contributions of various impurities to the dissolution energy are distinguished, and their influence on the binding energy of hydrogen and impurities is analyzed. The existence of a linear dependence of the energy of hydrogen dissolution on the magnitude of the change in the electron density of the intra-tetrahedral pore after the introduction of a hydrogen atom into it is shown. The results obtained made it possible to formulate the key mechanisms for controlling the localization of hydrogen in bcc iron by substitution impurities.

A STUDY OF CARBON NANOTUBES ENERGETICS USING ORBITAL FREE METHOD IN THE FRAME-WORK OF THE DENSITY FUNCTIONAL THEORY

2020 ◽  
Vol 7 (3) ◽  
pp. 29-36
Author(s):  
VICTOR ZAVODINSKY ◽  
◽  
OLGA GORKUSHA
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Tube Diameter ◽  
Tube Length ◽  
Functional Theory ◽  
The Third ◽  
The Density Functional Theory ◽  
Frame Work ◽  
Orbital Free

Dependence of the binding energy of carbon atoms in nanotubes on the tube diameter is studied. The full-electron orbital free modeling method, developed by us in the framework of the density functional theory, was used for calculation of the binding energy. Nanotubes of limited lengths with the armchair ends were investigated. The tube diameter D, was varied from 0,68 nm up to 1,50 nm; numbers of included atoms were changed from 80 up to 320. Three sets of tubes were studied: the tube length was 0,87 nm in the first set, 1,36 nm in second set, and 1,86 nm in the third set. For the first set the energy minimum (-7.50 eV) was found at Dmin = 1,22 nm, for the second set (-7.62 eV) at Dmin = 1.00 nm, and for the third set (-8.01 eV) at Dmin = 1.06 eV.

Magnetic Properties of Off-Stoichiometric Ni-X-In (X=Mn, Fe and Co) Magnetic Shape Memory Alloys by First-Principles Calculations

2014 ◽  
Vol 783-786 ◽  
pp. 2419-2422
Author(s):  
Jing Bai ◽  
Jean M. Raulot ◽  
Yu Dong Zhang ◽  
Claude Esling ◽  
Xiang Zhao ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
First Principles ◽  
Software Package ◽  
Density Functional ◽  
First Principles Calculations ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys ◽  
Functional Theory ◽  
The Density Functional Theory

The magnetic properties of the off-stoichiometric Ni2XIn (X=Mn, Fe, Co) are systematically investigated by means of the first–principles calculations within the framework of the density functional theory (DFT) using the Vienna ab initio software package (VASP). The magnitude of the variation in the Ni moments is much larger than that of Mn in the defective Ni2XIn. The value of the Ni magnetic moment sensitively depends on the distance between Ni and X.

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...

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...

Boron nitride zigzag nanoribbons: optimal thermoelectric systems

2015 ◽  
Vol 17 (34) ◽  
pp. 22448-22454 ◽  
Author(s):  
K. Zberecki ◽  
R. Swirkowicz ◽  
J. Barnaś
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Density Functional ◽  
Thermoelectric Effects ◽  
Functional Theory ◽  
Thermoelectric Systems ◽  
The Density Functional Theory ◽  
Boron Nitride Nanoribbons

Conventional and spin related thermoelectric effects in zigzag boron nitride nanoribbons are studied theoretically within the Density Functional Theory (DFT) approach.

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