scholarly journals Low compressible noble metal carbides with rocksalt structure: Ab initio total energy calculations of the elastic stability

2006 ◽  
Vol 89 (7) ◽  
pp. 071913 ◽  
Author(s):  
Chang-Zeng Fan ◽  
Song-Yan Zeng ◽  
Zai-Ji Zhan ◽  
Ri-Ping Liu ◽  
Wen-Kui Wang ◽  
...  
Keyword(s):  
Total Energy ◽  
Ab Initio ◽  
Noble Metal ◽  
Elastic Stability ◽  
Metal Carbides ◽  
Energy Calculations ◽  
Rocksalt Structure

AB-Initio Based Calculations of Vacancy Formation and Clustering Energies Including Lattice Relaxation in Fe3Al

1998 ◽  
Vol 538 ◽  
Author(s):  
Leonid S. Muratov ◽  
Bernard R. Cooper
Keyword(s):  
Total Energy ◽  
Ab Initio ◽  
Vacancy Formation ◽  
Attractive Interaction ◽  
Crystallographic Structure ◽  
Full Potential ◽  
Energy Calculations ◽  
Significant Difference ◽  
Simulation Cell ◽  
Ab Inito

AbstractVacancy formation and clustering significantly affect structural properties of transition-metal aluminides. Ab-initio quantum mechanical total-energy calculations using a full-potential linear combination of muffin-tin orbitals (LMTO) technique provide a convenient method of studying relevant characteristics such as changes in density of states, and charge redistribution around defects. Augmented with Hellmann-Feymann forces, LMTO allows calculations of relaxation geometries and relaxation energies. We have performed such calculations for vacancies and antisite substitutional point defects in Fe3Al with DO3 crystallographic structure. There are two limiting factors complicating calculations of defect formation energies directly from ab-inito calculations. The first is that a single defect, due to the lattice periodicity necessitated by the use of ab-inito total energy techniques, cannot be considered as an isolated defect, even in the maximum computable simulation cell. Unlike previous calculations [ I ], which did not find a dependency on the size of the simulation cell, our calculations have shown a significant difference in results for 32- and 16- atom cells. This difference provides information about vacancy clustering since it can be explained by a relatively small attractive interaction energy ~0.2 eV between two vacancies located in adjacent simulation cells and separated by the lattice constant distance (5.52Å) [2]. By comparing the internal energies for two configurations of 30 atom cells (32 atom - 2 vacancies) we were able to estimate that the attractive interaction between two vacancies could reach 1.2 eV. The second complication is the fact that chemical potentials of elements cannot be directly extracted from the total energy calculations for the compound. To deal with this problem, we considered two possible approximations and compared results, which were found to be quite similar for iron vacancies.

Crystal structure prediction of LiBeH3 using ab initio total-energy calculations and evolutionary simulations

2008 ◽  
Vol 129 (23) ◽  
pp. 234105 ◽  
Author(s):  
Chao-Hao Hu ◽  
A. R. Oganov ◽  
Y. M. Wang ◽  
H. Y. Zhou ◽  
A. Lyakhov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Total Energy ◽  
Ab Initio ◽  
Structure Prediction ◽  
Crystal Structure Prediction ◽  
Energy Calculations ◽  
Evolutionary Simulations

Ab initio total energy calculations of the optical properties of the CdSnP2 ternary pnictide semiconductor

2004 ◽  
Vol 298 (1-3) ◽  
pp. 135-140 ◽  
Author(s):  
F. Chiker ◽  
B. Abbar ◽  
H. Aourag ◽  
A. Tadjer ◽  
S. Bresson ◽  
...  
Keyword(s):  
Optical Properties ◽  
Total Energy ◽  
Ab Initio ◽  
Energy Calculations

Ab-Initio Calculation of Migration Energies of Adatoms on the Si (100) Surface

1991 ◽  
Vol 02 (01) ◽  
pp. 288-291
Author(s):  
G. BROCKS ◽  
P.J. KELLY ◽  
R. CAR
Keyword(s):  
Total Energy ◽  
Ab Initio ◽  
First Principles ◽  
Binding Sites ◽  
Ab Initio Calculation ◽  
Saddle Points ◽  
Energy Calculations ◽  
Important Chemical

The binding sites for adsorption of a single Si atom on the reconstructed Si (100) surface are identified using first-principles total energy calculations. By mapping out the total energy as a function of the position of the adatom on the surface, we establish several saddle points for migration over the surface. Similar calculations for P and Al adatoms establish the most important chemical trend.

scholarly journals Shell model of BaTiO3 derived from ab-initio total energy calculations

2013 ◽  
Vol 114 (17) ◽  
pp. 174108 ◽  
Author(s):  
J. M. Vielma ◽  
G. Schneider
Keyword(s):  
Total Energy ◽  
Ab Initio ◽  
Shell Model ◽  
Energy Calculations
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