Determination of Ga Self-Diffusion Coefficient in GaAs

1991 ◽  
Vol 240 ◽  
Author(s):  
T. Y. Tan ◽  
S. Yu ◽  
U. Gösele
Keyword(s):  
Diffusion Coefficient ◽  
Quantitative Determination ◽  
Thermal Equilibrium ◽  
Activation Enthalpy ◽  
Self Diffusion ◽  
Self Diffusion Coefficient ◽  
Positively Charged

ABSTRACTA quantitative determination of the contributions of the triply-negatively charged Ga vacancies and of the doubly-positively charged Ga self-interstitials to Ga self-diffusion coefficient in GaAs has been carried out. Unde thermal equilibrium and intrinsic conditions, the contribution is characterized by an activation enthalpy of 6 eV for As-rich crystals and of 7.52 eV for Ga-rich crystals, while the contribution is characterized by an activation enthalpy of 4.89 eV for As-rich crystals and of 3.37 eV for Ga-rich crystals.

PARAMETERIZATION OF COARSE GRAINED FORCE FIELDS FOR DYNAMIC PROPERTY OF ETHYLENE GLYCOL OLIGOMERS/WATER BINARY MIXTURES

2013 ◽  
Vol 12 (06) ◽  
pp. 1350051 ◽  
Author(s):  
TAMIO YAMAZAKI
Keyword(s):  
Diffusion Coefficient ◽  
Ethylene Glycol ◽  
Dynamic Properties ◽  
Md Simulations ◽  
Coarse Grained ◽  
Self Diffusion ◽  
Molecular Weights ◽  
Self Diffusion Coefficient ◽  
Glycol Oligomers

To evaluate shear viscosity of ethylene glycol oligomers (EGO)/water binary mixture by means of coarse-grained molecular dynamics (CG-MD) simulations, we proposed the self-diffusion-coefficient-based parameterization of non-bonded interactions among CG particles. Our parameterization procedure consists of three steps: (1) determination of bonded potentials, (2) scaling for time and solvent diffusivity and (3) optimization of Lennard-Jones parameters to reproduce experimental self-diffusion coefficient and density data. With the determined parameters and the scaling relations, we evaluated shear viscosities of aqueous solutions of EGOs with various molecular weights and concentrations. Our simulation results are in close agreement with the experimental data. The largest simulation in this article corresponds to a 1.2 μs atomistic simulation for 100,000 atoms. Our CG model with the parameterization scheme for CG particles may be useful to study the dynamic properties of a liquid which contains relatively low molecular weight polymers or oligomers.

Determination of Diffusion Coefficient of Cation Vacancies in Nickel Oxide

1969 ◽  
Vol 24 (3) ◽  
pp. 441-443 ◽  
Author(s):  
Romano Morlotti
Keyword(s):  
Electrical Conductivity ◽  
Diffusion Coefficient ◽  
Nickel Oxide ◽  
Equilibrium Concentration ◽  
The Self ◽  
Self Diffusion ◽  
Partial Pressures ◽  
Self Diffusion Coefficient ◽  
Good Agreement

AbstractPolycrystalline NiO samples were equilibrated with different oxygen partial pressures from 10-3 to 1 Atm in the temperature range 750 °C -1000 °C. Transient electrical conductivity was measured until a new equilibrium was attained after changing the oxygen partial pressure. By the time dependence of the electrical conductivity in isothermal conditions the diffusion coefficient of nickel vacancies was determined. Using the pertinent value for the vacancies equilibrium concentration, the self-diffusion coefficient of nickel in nickel oxide was obtained in good agreement with literature data.

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