A molecular dynamics study of structural relaxation in tetrahedrally coordinated nanocrystals

2007 ◽  
Vol 9 (19) ◽  
pp. 2355 ◽  
Author(s):  
Benjamin J. Morgan ◽  
Paul A. Madden
Keyword(s):  
Molecular Dynamics ◽  
Structural Relaxation

scholarly journals Origin of the enhanced structural and reorientational relaxation rates in the presence of relatively weak dc electric fields

2004 ◽  
Vol 76 (1) ◽  
pp. 215-221 ◽  
Author(s):  
A. Vegiri
Keyword(s):  
Molecular Dynamics ◽  
Electric Field ◽  
Electric Fields ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Common Mechanism ◽  
Weak Electric Field ◽  
Water Molecules ◽  
Relaxation Rates ◽  
Dynamics Simulations

The origin of the dramatic increase of the reorientational and structural relaxation rates of single water molecules in clusters of size N = 16, 32, and 64 at T = 200 K, under the influence of an external, relatively weak electric field (~0.5 107 V/cm) is examined through molecular dynamics simulations. The observed effect is attributed not to any profound structural changes, but to the increase of the size of the molecular cage. The response of water to an electric field in this range shows many similarities with the dynamics of water under low pressure. By referring to simulations and experiments from the literature, we show that in both cases the observed effects are dictated by a common mechanism.

Structural relaxation in Ag-Ni nanoparticles: Atomistic modeling away from equilibrium

2021 ◽  
Author(s):  
Florent Calvo
Keyword(s):  
Molecular Dynamics ◽  
Structural Relaxation ◽  
Rare Events ◽  
Metal Vapor ◽  
Silver Concentration ◽  
Atomistic Modeling ◽  
Ni Nanoparticles ◽  
Vapor Mixture ◽  
Chemical Ordering ◽  
Fast Cooling

The out-of-equilibrium structural relaxation of Ag-Ni nanoparticles containing about 1000--3000 atoms was investigated computationally by means of molecular dynamics trajectories in which the temperature is decreased gradually over hundreds of nanoseconds. At low silver concentration of 10--30\%, the evolution of chemical ordering in Ni$_{\rm core}$Ag$_{\rm shell}$ nanoparticles with different surface arrangements is found to proceed spontaneously and induce some rounding of the nickel core and its partial recristallization. Fast cooling of an initially hot metal vapor mixture was also considered, and it is shown to disfavor silver aggregation at the surface. Silver impurities are also occasionally produced but remain rare events under the conditions of our simulations.

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