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%!TEX root = /Users/charles/Desktop/nanoglass/nanoglass.tex |
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\section{Computational Methodology} |
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\label{sec:details} |
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Cu-core / Ag-shell and random alloy structures were constructed on an |
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underlying FCC lattice (4.09 {\AA}) at the bulk eutectic composition |
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$\mathrm{Ag}_6\mathrm{Cu}_4$. Three different sizes of nanoparticles |
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$\mathrm{Ag}_6\mathrm{Cu}_4$. All three compositions were considered although experimental results suggest that the random structure is the most likely composition after synthesis.\cite{Jiang:2005lr,gonzalo:5163} Three different sizes of nanoparticles |
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corresponding to a 20 \AA radius (1961 atoms), 30 {\AA} radius (6603 |
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atoms) and 40 {\AA} radius (15683 atoms) were constructed. These |
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initial structures were relaxed to their equilibrium structures at 20 |
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K for 20 ps and again at 300 K for 100 ps sampling from a |
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Maxwell-Boltzmann distribution at each temperature. |
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Maxwell-Boltzmann distribution at each temperature. |
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To mimic the effects of the heating due to laser irradiation, the |
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particles were allowed to melt by sampling velocities from the Maxwell |
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$2\alpha_{ij}$ and include up to the sixth coordination shell in FCC |
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metals. |
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\subsection{Sampling single-temperature configurations from a cooling |
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trajectory} |
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%\subsection{Sampling single-temperature configurations from a cooling |
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%trajectory} |
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ffdsafjdksalfdsa |
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To better understand the structural changes occurring in the nanoparticles throughout the cooling trajectory, configurations were sampled at temperatures throughout the cooling trajectory. These configurations were then allowed to evolve under NVE dynamics to sample from the proper distribution in phase space. Figure \ref{fig:images_cooling_time_traces} illustrates this sampling. |
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\begin{figure}[htbp] |
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\centering |
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\includegraphics[height=3in]{images/cooling_time_traces.pdf} |
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\caption{Illustrative cooling profile for the 40 {\AA} nanoparticle evolving under stochastic boundary conditions corresponding to $G=$$87.5\times 10^{6}$ $(\mathrm{Wm^{-2}K^{-1}})$. At temperatures along the cooling trajectory, configurations were sampled and allowed to evolve in the NVE ensemble. These subsequent trajectories were analyzed for structural features associated with bulk glass formation.} |
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\label{fig:images_cooling_time_traces} |
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\end{figure} |
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