scholarly journals Molecular Dynamics Simulation of Zener Pinning by Differently Shaped and Oriented Particles

2021 ◽  
Vol 8 ◽  
Author(s):  
Yi Li ◽  
Jian Zhou ◽  
Runjie Li ◽  
Qingyu Zhang
Keyword(s):  
Molecular Dynamics ◽  
Dynamics Simulation ◽  
Pinning Force ◽  
Theoretical Studies ◽  
Constant Energy ◽  
Zener Pinning ◽  
Interaction Processes ◽  
Interface Characteristics ◽  
Theoretical Predictions ◽  
Ag Particle

Zener pinning between a curved Cu grain boundary (GB) and a differently shaped and oriented Ag particle has been simulated via molecular dynamics. The computed magnitudes of the maximum pinning force agreed with theoretical predictions only when the force was small. As the force increased, discrepancy became obvious. Through careful inspection of the structures of the Cu–Ag interfaces, detailed interaction processes, and variation of the Cu GB during the interaction, the discrepancy is found to correlate with GB faceting, which very likely reduces the maximum pinning force and facilitates boundary passage. GB anisotropy and/or interface characteristics are also found to slightly contribute to the discrepancy. These findings suggest that the assumption of an isotropic GB with constant energy utilized in previous theoretical studies for deriving the maximum pinning force might be inappropriate and that an accurate maximum pinning force could not be predicted without knowing the effects of GB evolution together with detailed properties of both GBs and interfaces.

Momentum Removal to Obtain the Position-Dependent Diffusion Constant in Constrained Molecular Dynamics Simulation

2021 ◽  
Author(s):  
Kazushi Fujimoto ◽  
Tetsuro Nagai ◽  
Tsuyoshi Yamaguchi
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Mass Velocity ◽  
Center Of Mass ◽  
Heterogeneous Systems ◽  
Diffusion Constant ◽  
Dynamics Simulation ◽  
Coulombic Interaction ◽  
Ewald Method ◽  
Theoretical Predictions

<div>The position-dependent diffusion coefficient along with free energy profile are important parameters needed to study mass transport in heterogeneous systems such as biological and polymer membranes, and molecular dynamics (MD) calculation is a popular tool to obtain them. Among many methodologies, the Marrink-Berendsen (MB) method is often employed to calculate the position-dependent diffusion coefficient, in which the autocorrelation function of the force on a fixed molecule is related to the friction on the molecule. However, the diffusion coefficient is shown to be affected by the period of the removal of the center-of-mass velocity, which is necessary when performing MD calculations using the Ewald method for Coulombic interaction. We have clarified theoretically in this study how this operation affects the diffusion coefficient calculated by the MB method, and the theoretical predictions are proven by MD calculations. Therefore, we succeeded in providing guidance on how to select an appropriate the period of the removal of the center-of-mass velocity in estimating the position-dependent diffusion coefficient by the MB method. This guideline is applicable also to the Woolf-Roux method.</div>

Momentum Removal to Obtain the Position-Dependent Diffusion Constant in Constrained Molecular Dynamics Simulation

2021 ◽  
Author(s):  
Kazushi Fujimoto ◽  
Tetsuro Nagai ◽  
Tsuyoshi Yamaguchi
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Mass Velocity ◽  
Center Of Mass ◽  
Heterogeneous Systems ◽  
Diffusion Constant ◽  
Dynamics Simulation ◽  
Coulombic Interaction ◽  
Ewald Method ◽  
Theoretical Predictions

<div>The position-dependent diffusion coefficient along with free energy profile are important parameters needed to study mass transport in heterogeneous systems such as biological and polymer membranes, and molecular dynamics (MD) calculation is a popular tool to obtain them. Among many methodologies, the Marrink-Berendsen (MB) method is often employed to calculate the position-dependent diffusion coefficient, in which the autocorrelation function of the force on a fixed molecule is related to the friction on the molecule. However, the diffusion coefficient is shown to be affected by the period of the removal of the center-of-mass velocity, which is necessary when performing MD calculations using the Ewald method for Coulombic interaction. We have clarified theoretically in this study how this operation affects the diffusion coefficient calculated by the MB method, and the theoretical predictions are proven by MD calculations. Therefore, we succeeded in providing guidance on how to select an appropriate the period of the removal of the center-of-mass velocity in estimating the position-dependent diffusion coefficient by the MB method. This guideline is applicable also to the Woolf-Roux method.</div>

Molecular-Dynamics Simulation of the Interaction Processes of Pulsed Ion Beams with Metals

2020 ◽  
Vol 14 (6) ◽  
pp. 1342-1345
Author(s):  
I. V. Puzynin ◽  
T. P. Puzynina ◽  
I. G. Hristov ◽  
R. D. Hristova ◽  
Z. K. Tukhliev ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Ion Beams ◽  
Dynamics Simulation ◽  
Interaction Processes

scholarly journals Molecular dynamics simulation of vapour-liquid nucleation of water with constant energy

2015 ◽  
Vol 92 ◽  
pp. 02013 ◽  
Author(s):  
Michal Duška ◽  
Tomáš Němec ◽  
Jan Hrubý ◽  
Václav Vinš ◽  
Barbora Planková
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Constant Energy

Translational and rotational dynamics in supercritical methanol from molecular dynamics simulation

2004 ◽  
Vol 76 (1) ◽  
pp. 203-213 ◽  
Author(s):  
Michalis Chalaris ◽  
J. Samios
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Md Simulation ◽  
Time Correlation ◽  
The Self ◽  
Dynamics Simulation ◽  
Supercritical Methanol ◽  
Reorientational Motion ◽  
Self Diffusion ◽  
Theoretical Predictions

The purpose of this paper is to review our latest molecular dynamics (MD) simulation studies on the temperature and density dependence of the translational and reorientational motion in supercritical (SC) methanol. In the present treatment, Jorgensen's [W. L. Jorgensen. J. Phys. Chem. A102, 8641 (1998)] transferable potential model, tested in a recent MD study of hydrogen bonds in this fluid [M. Chalaris and J. Samios, J. Phys. Chem. B103, 1161 (1999)], was employed to simulate the dynamics of the system. The simulations were performed in the canonical (NVT) ensemble along the isotherms 523, 623, and 723 K and densities corresponding to the pressures from 10 to 30 MPa. Several dynamical properties of the fluid have been obtained and analyzed in terms of appropriate time-correlation functions (CFs). With respect to the translational dynamics, the self-diffusion coefficients obtained have been used to test the applicability of the well-known Chapman-Enskog kinetic theory. We have found that the theoretical predictions for the self-diffusion coefficients are only in qualitative agreement with the MD results over the whole temperature and density range studied. Finally, the inspection of the reorientational CFs and their corresponding correlation times lead to the conclusion that the reorientational motion of the SC methanol molecules in the sample is anisotropic.

Molecular Dynamics Simulation of Nanodroplet Evaporation

2000 ◽  
Vol 123 (4) ◽  
pp. 741-748 ◽  
Author(s):  
J. H. Walther ◽  
P. Koumoutsakos
Keyword(s):  
Molecular Dynamics ◽  
Heat Conduction ◽  
Data Structure ◽  
Dynamics Simulation ◽  
Evaporation Coefficient ◽  
Theoretical Predictions ◽  
Tree Data ◽  
Convergence Study ◽  
Dynamics Simulations ◽  
Tree Data Structure

Molecular dynamics simulations are used to study the sub-critical evaporation of a nanometer-size droplet at 300 K and 3 MPa. Classical molecular dynamics techniques are combined with an adaptive tree data structure for the construction of the neighbor lists, allowing efficient simulations using hundreds of thousands of molecules. We present a systematic convergence study of the method demonstrating its convergence for heat conduction problems in submicron scales. These high resolution simulations compute values of the evaporation coefficient that are in excellent agreement with theoretical predictions.

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