scholarly journals Vacancy diffusion in palladium hydrides

2021 ◽  
Author(s):  
Jonathan Marc Polfus ◽  
Thijs Andries Peters ◽  
Rune Bredesen ◽  
Ole Martin Løvvik
Keyword(s):  
Density Functional Theory ◽  
Kinetic Parameters ◽  
Diffusion Coefficients ◽  
Density Functional ◽  
The Self ◽  
Vacancy Diffusion ◽  
Functional Theory ◽  
Self Diffusion ◽  
Thermodynamic And Kinetic Parameters

The self-diffusion coefficients of palladium in PdHx (x = 0, 0.25, 0.5, 0.75, 1) were studied using density functional theory to obtain the required thermodynamic and kinetic parameters. The enthalpy...

Embedded atom model for the liquid U–10Zr alloy based on density functional theory calculations

RSC Advances ◽  
2015 ◽  
Vol 5 (76) ◽  
pp. 61495-61501 ◽  
Author(s):  
Ning Wang ◽  
Tao Jiang ◽  
Yanqiu Yang ◽  
Jie Tian ◽  
Sheng Hu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Correlation Coefficient ◽  
Linear Correlation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
The Self ◽  
Activation Process ◽  
Functional Theory ◽  
Self Diffusion ◽  
Embedded Atom

The self-diffusion in liquid U–10Zr alloy obeyed the Arrhenius activation process; the linear correlation coefficient was about 0.98.

Effect of C on Vacancy Migration in α-Iron

2008 ◽  
Vol 139 ◽  
pp. 157-164 ◽  
Author(s):  
Chu Chun Fu ◽  
Estelle Meslin ◽  
Alain Barbu ◽  
F. Willaime ◽  
V. Oison
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Model ◽  
High Purity ◽  
Diffusion Coefficients ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Vacancy Diffusion ◽  
Covalent Bonds ◽  
Functional Theory ◽  
Limiting Case

Carbon atoms are always present in Fe-based materials, either as impurities even in high purity samples or as an intrinsic constituent in steels. Density Functional Theory calculations have been performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find that the formation of VCn complexes is energetically favourable for n ≤ 3, with VC2 being the most stable one. The energy gain corresponding to the clustering reaction VCn-1 + C → VCn depends mainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantly modified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour. Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature and carbon content using a simplified thermodynamic model. The results are discussed in detail in the limiting case of excess of C with respect to vacancies.

scholarly journals Insight into the Self-Assembly of Water-Soluble Perylene Bisimide Derivatives Through a Combined Computational and Experimental Approach

2019 ◽  
Author(s):  
Emily R. Draper ◽  
Liam Wilbraham ◽  
Dave J. Adams ◽  
Matthew Wallace ◽  
Martijn Zwijnenburg
Keyword(s):  
Density Functional Theory ◽  
Self Assembly ◽  
Density Functional ◽  
Colloidal Stability ◽  
Water Soluble ◽  
The Self ◽  
Functional Theory ◽  
Perylene Bisimide ◽  
Aggregate Growth ◽  
Perylene Bisimides

We use a combination of computational and experimental techniques to study the self-assembly and gelation of water-soluble perylene bisimides derivatised at the imide position with an amino acid. Specifically, we study the likely structure of self-assembled aggregates of the alanine-functionalised perylene bisimide (PBI-A) and the thermodynamics of their formation using density functional theory and predict the UV-vis spectra of such aggregates using time-dependent density functional theory. We compare these predictions to experiments in which we study the evolution of the UV-Vis and NMR spectra and rheology of alkaline PBI-A solutions when gradually decreasing the pH. Based on the combined computational and experimental results, we show that PBI-A self-assembles at all pH values but that aggregates grow in size upon protonation. Gelation is driven not by aggregate growth but reduction of the aggregation surface-charge and a decrease in the colloidal stability of the aggregation with respect to agglomeration.

Modeling of Atomistic Processes in Semiconductors: from Defect Signatures to a Hierarchy of Annealing Mechanisms

2006 ◽  
Vol 978 ◽  
Author(s):  
Michel Bockstedte
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
The Self ◽  
Functional Theory ◽  
Dopant Activation ◽  
Defect Centers ◽  
The Density Functional Theory ◽  
Modeling And Experiments ◽  
Microscopic Origin

AbstractThe modeling of atomistic processes in semiconductors based on the density functional theory is outlined. The role of intrinsic defects in the self and dopant diffusion, as well as in the dopant activation is investigated for the case of silicon carbide. A hierarchy of annealing mechanisms for vacancies and interstitials is proposed. The identification of the microscopic origin of experimental defect centers by calculated defect signatures establishes a link between theoretical modeling and experiments.

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