scholarly journals Self-diffusion coefficient of the square-well fluid from molecular dynamics simulations within the constant force approach

2018 ◽  
Vol 149 (14) ◽  
pp. 144501
Author(s):  
Alexis Torres-Carbajal ◽  
Victor M. Trejos ◽  
Luz Adriana Nicasio-Collazo
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Molecular Dynamics Simulations ◽  
Constant Force ◽  
Self Diffusion ◽  
Square Well ◽  
Dynamics Simulations ◽  
Self Diffusion Coefficient

Molecular Dynamics Simulation of the Internal Mobilities in Molten (Dy1/3,K)Cl

2001 ◽  
Vol 56 (3-4) ◽  
pp. 273-278 ◽  
Author(s):  
Masahiko Matsumiya ◽  
Ryuzo Takagi
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Molecular Dynamics Simulation ◽  
Molecular Dynamics Simulations ◽  
Dynamics Simulation ◽  
Self Diffusion ◽  
Electrical Conductivities ◽  
Internal Mobility ◽  
Dynamics Simulations ◽  
Self Diffusion Coefficient

Abstract Molecular dynamics simulations have been performed on molten (Dy1/3,K)Cl at 1093 K in order to compare the calculated self-exchange velocity (SEV), self-diffusion coefficient (D) and electrical con­ductivity with the corresponding experimental results. It was found that SEV, v, and D of potassium de­ crease with increasing concentration of dysprosium, as expected from the internal mobility, b. The decrease of bK, vK, and DK are ascribed to the tranquilization effect by Dy3+ which strongly inter­ acts with CP. On the contrary, bDy, vDy, and DDy increase with increasing concentration of Dy3+. This may be attributed to the stronger association of Dy3+ with Cl- due to the enhanced charge asym­ metry of the two cations neighboring to the Cl-. In addition, the sequence of the calculated SEV's, D's and electrical conductivities for the various compositions were consistent with those of the referred ex­ perimental results.

scholarly journals Evidence for Glass Behavior in Amorphous Carbon

2020 ◽  
Vol 6 (3) ◽  
pp. 50 ◽  
Author(s):  
Steven Best ◽  
Jake B. Wasley ◽  
Carla de Tomas ◽  
Alireza Aghajamali ◽  
Irene Suarez-Martinez ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Glass Transition ◽  
Transition Temperature ◽  
Amorphous Carbon ◽  
The Self ◽  
Self Diffusion ◽  
Dynamics Simulations ◽  
Self Diffusion Coefficient ◽  
Glass Behavior

Amorphous carbons are disordered carbons with densities of circa 1.9–3.1 g/cc and a mixture of sp2 and sp3 hybridization. Using molecular dynamics simulations, we simulate diffusion in amorphous carbons at different densities and temperatures to investigate the transition between amorphous carbon and the liquid state. Arrhenius plots of the self-diffusion coefficient clearly demonstrate that there is a glass transition rather than a melting point. We consider five common carbon potentials (Tersoff, REBO-II, AIREBO, ReaxFF and EDIP) and all exhibit a glass transition. Although the glass-transition temperature (Tg) is not significantly affected by density, the choice of potential can vary Tg by up to 40%. Our results suggest that amorphous carbon should be interpreted as a glass rather than a solid.

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