scholarly journals Ab initio theory of noble gas atoms in bcc transition metals

2018 ◽  
Vol 20 (25) ◽  
pp. 17048-17058 ◽  
Author(s):  
Chao Jiang ◽  
Yongfeng Zhang ◽  
Yipeng Gao ◽  
Jian Gan

Systematic ab initio calculations based on density functional theory have been performed to gain fundamental understanding of the interactions between noble gas atoms (He, Ne, Ar and Kr) and bcc transition metals in groups 5B (V, Nb and Ta), 6B (Cr, Mo and W) and 8B (Fe).

2021 ◽  
Vol 63 (7) ◽  
pp. 830
Author(s):  
М.С. Ракитин ◽  
А.А. Мирзоев

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.


2006 ◽  
Vol 987 ◽  
Author(s):  
M. Zemzemi ◽  
M. Hebbache ◽  
D. Zivkovic ◽  
L Stuparevic

AbstractTransition metals of the platinum group (Os, Ir, Pt, Ru, Re, Rh) do not form carbides and nitrides at ambient pressure. Osmium carbide seems to have been synthesized at zero pressure by Kempter and Nadler forty six years ago. According to the authors, OsC crystallizes in WC-type structure and has a hardness equal to 2000 kg mm-2. Up to date, no other experimental confirmation is available. We studied the electronic and mechanical properties of this hypothetical carbide using an approach based on the density-functional theory. We found that the work of the above mentioned authors is sound. The calculated lattice parameters are in good agreement with that given by those authors and a rough estimate also showed that the hardness given by them is reasonable. However, we found that the hexagonal structure of osmium carbide is electronically and mechanically unstable.


1986 ◽  
Vol 70 ◽  
Author(s):  
Yaneer Bar-Yam ◽  
J. D. Joannopoulos

ABSTRACTIt has recently become feasible that theory Will be able to predict the structure of solids “ab-initio”, using only the atomic number of the constituent atoms as input. This is based on recent advances in density-functional theory and pseudopotential theory. A simple physical introduction of the concepts underlying these theories is presented. Special emphasis is given to examining the structure and effective correlation energies of defects in amorphous Si.


1999 ◽  
Vol 23 (8) ◽  
pp. 502-503
Author(s):  
Branko S. Jursic

High level ab initio and density functional theory studies are performed on highly protonated methane species.


Author(s):  
Alberto Rodríguez-Fernández ◽  
Laurent Bonnet ◽  
Pascal Larrégaray ◽  
Ricardo Díez Muiño

The dissociation process of hydrogen molecules on W(110) was studied using density functional theory and classical molecular dynamics.


Nanoscale ◽  
2020 ◽  
Author(s):  
Shashikant Kumar ◽  
David Codony ◽  
Irene Arias ◽  
Phanish Suryanarayana

We study the flexoelectric effect in fifty-four select atomic monolayers using ab initio Density Functional Theory (DFT). Specifically, considering representative materials from each of Group III monochalcogenides, transition metal dichalcogenides...


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