Prediction of Diffusion Coefficients in Liquid and Solids

2015 ◽  
Vol 364 ◽  
pp. 182-191 ◽  
Author(s):  
William Yi Wang ◽  
Bi Cheng Zhou ◽  
Jia Jia Han ◽  
Hua Zhi Fang ◽  
Shun Li Shang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
First Principles ◽  
Diffusion Coefficients ◽  
Tracer Diffusion ◽  
First Principles Calculations ◽  
Dominant Contribution ◽  
Creep Properties ◽  
Exchange Correlation ◽  
Self Diffusion ◽  
Tracer Diffusion Coefficients

Our activities in predicting diffusion coefficients in fcc, bcc, and hcp solid solutions using first-principles calculations and in liquid usingabinitiomolecular dynamics are reviewed. These include self-diffusion coefficients [1-4], tracer diffusion coefficients in dilute solutions [5-7], calculation of migration entropy [8], tracer diffusion coefficients in metallic and oxide liquid [9, 10], and effects of vacancy on diffusion of oxygen [11, 12]. The effects of exchange correlation functionals are examined in some cases along with charge transfer between solute and solvent elements. The dominant contribution of diffusion on the effects of Re addition on the creep properties of Ni-base superalloys is discussed [13].

CALCULATIONS OF SELF-DIFFUSION PROCESS AND COEFFICIENT IN ORDERED B2 AlCo

2013 ◽  
Vol 27 (19) ◽  
pp. 1341034
Author(s):  
ZHI-SHENG NONG ◽  
JING-CHUAN ZHU ◽  
YONG CAO ◽  
XIA-WEI YANG ◽  
ZHONG-HONG LAI ◽  
...  
Keyword(s):  
Diffusion Process ◽  
First Principles ◽  
Diffusion Coefficients ◽  
Density Functional ◽  
Nearest Neighbor ◽  
The Self ◽  
First Principles Calculations ◽  
Self Diffusion ◽  
Diffusion Mechanisms ◽  
Semi Empirical

The self-diffusion process in B2 type intermetallic compound AlCo has been investigated by the first-principles calculations within the frame work of density functional theory (DFT). The obtained mono-vacancy formation, migration and activation energies for four self-diffusion mechanisms, the next-nearest-neighbor (NNN) jump, [110] six-jump cycle (6JC), straight [100] 6JC and bent [100] 6JC diffusion show that the NNN jump mechanism of Co vacancy requires the lowest activation energy (Q = 6.835 eV ) in these diffusion mechanisms, which indicates that it is the main way of self-diffusion in AlCo . The electronic structure including the electron density difference on (-1 1 0) plane as well as atomic Mulliken populations were calculated, and the change of bonding behavior during the [110] 6JC process was discussed in detail. Finally, the self-diffusion coefficients of NNN jump and 6JC mechanisms for AlCo were also studied via the first-principles calculations and semi-empirical predictions, which indicates that the self-diffusion coefficients for NNN jump of Co vacancy show the highest value than the others.

Tracer diffusion coefficients of tritiated water and acetonitrile in water + acetonitrile mixtures

1980 ◽  
Vol 33 (8) ◽  
pp. 1667 ◽  
Author(s):  
AJ Easteal
Keyword(s):  
Diffusion Coefficients ◽  
Structural Model ◽  
Tritiated Water ◽  
Tracer Diffusion ◽  
Solution Viscosity ◽  
Composition Region ◽  
Self Diffusion ◽  
Composition Variation ◽  
Diaphragm Cell ◽  
Tracer Diffusion Coefficients

Tracer diffusion coefficients of tritiated water (HTO) and 14C-labelled acetonitrile have been measured at 298.15 K by the diaphragm cell method, for the whole range of compositions of water+ acetonitrile binary mixtures. The composition variation of (a) the deviation of D from additivity and (b) the product Dη, for each component, has been evaluated. The variation of Dη is discussed in terms of the Naberukhin- Rogov structural model for solutions of non-electrolytes in water. ��� The diffusion data have been used to test a semiempirical relationship, between solution viscosity and self-diffusion coefficients, due to Albright. For the composition region of 5-55 mole % acetonitrile Albright's equation gives calculated viscosities which agree well with observed values. The calculation fails to reproduce the observed variation of viscosity for the composition region of 60-95 mole % acetonitrile.

Arsenic Diffusion in Intrinsic Gallium Arsenide

1998 ◽  
Vol 527 ◽  
Author(s):  
G. Bösker ◽  
N.A. Stolwijk ◽  
H. Mehrer ◽  
U. Södervall ◽  
J.V. Thordson ◽  
...  
Keyword(s):  
Gallium Arsenide ◽  
Mass Spectroscopy ◽  
Diffusion Coefficients ◽  
Nitrogen Doping ◽  
Tracer Diffusion ◽  
Substantial Contribution ◽  
Ambient Conditions ◽  
Self Diffusion ◽  
Tracer Diffusion Coefficients ◽  
Secondary Ion

ABSTRACTSelf-diffusion on the As sublattice in intrinsic GaAs was investigated in a direct way by As tracer diffusion measurements using the radioisotopes 73As and 76As and in an indirect way by annealing of buried nitrogen doping layers in epitaxially grown GaAs/GaAs:N heterostructures. The latter experiments were analyzed by secondary ion mass spectroscopy and interpreted within the framework of the kick-out mechanism yielding the As diffusivities mediated by As interstitials IAs. Comparison of with tracer diffusion coefficients – including data reported in the literature–points to a substantial contribution of IAs to As diffusion in intrinsic GaAs under As-rich ambient conditions.

scholarly journals Carbon Diffusion in Cementite: A Molecular Dynamics Study

2009 ◽  
Vol 283-286 ◽  
pp. 24-29 ◽  
Author(s):  
Elena V. Levchenko ◽  
Alexander V. Evteev ◽  
Irina V. Belova ◽  
Graeme E. Murch
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Diffusion Coefficients ◽  
Activation Parameters ◽  
Carbon Diffusion ◽  
Tracer Diffusion ◽  
Dynamics Simulation ◽  
Temperature Range ◽  
Tracer Diffusion Coefficients

. In this paper, carbon diffusion in cementite is studied by molecular dynamics simulation. An assumption that carbon-carbon interaction occurs only indirectly via neighbouring iron atoms is used. An interstitial mechanism of carbon diffusion in cementite is revealed. The principal tracer diffusion coefficients and activation parameters of carbon diffusion in cementite are calculated for the temperature range 1223-1373 K and compared with the available published experimental data.

scholarly journals Modelling the Diffusion Coefficients of Dilute Gaseous Solutes in Hydrocarbon Liquids

2021 ◽  
Vol 42 (10) ◽  
Author(s):  
Yasser A. Aljeshi ◽  
Malyanah Binti Mohd Taib ◽  
J. P. Martin Trusler
Keyword(s):  
Carbon Dioxide ◽  
Diffusion Coefficients ◽  
Hard Sphere ◽  
Tracer Diffusion ◽  
Pure Component ◽  
Viscosity Data ◽  
Polar Liquids ◽  
Self Diffusion ◽  
Coefficient Measurement ◽  
Tracer Diffusion Coefficients

AbstractIn this work, we present a model, based on rough hard-sphere theory, for the tracer diffusion coefficients of gaseous solutes in non-polar liquids. This work extends an earlier model developed specifically for carbon dioxide in hydrocarbon liquids and establishes a general correlation for gaseous solutes in non-polar liquids. The solutes considered were light hydrocarbons, carbon dioxide, nitrogen and argon, while the solvents were all hydrocarbon liquids. Application of the model requires knowledge of the temperature-dependent molar core volumes of the solute and solvent, which can be determined from pure-component viscosity data, and a temperature-independent roughness factor which can be determined from a single diffusion coefficient measurement in the system of interest. The new model was found to correlate the experimental data with an average absolute relative deviation of 2.7 %. The model also successfully represents computer-simulation data for tracer diffusion coefficients of hard-sphere mixtures and reduces to the expected form for self-diffusion when the solute and solvent become identical.

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