| 48 |
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metallic atoms and the solvent, the effective viscosity is a |
| 49 |
|
essentially a free parameter that must be tuned to give experimentally |
| 50 |
|
relevant simulations. |
| 51 |
< |
|
| 51 |
> |
\begin{figure}[htbp] |
| 52 |
> |
\centering |
| 53 |
> |
\includegraphics[width=\linewidth]{images/stochbound.pdf} |
| 54 |
> |
\caption{Methodology for nanoparticle cooling. Equations of motion for metal atoms contained in the outer 4 {\AA} were determined by Langevins' Equations of motion. Metal atoms outside this region were allowed to evolve under Newtonian dynamics.} |
| 55 |
> |
\label{fig:langevinSketch} |
| 56 |
> |
\end{figure} |
| 57 |
|
The viscosity ($\eta$) can be tuned by comparing the cooling rate that |
| 58 |
|
a set of nanoparticles experience with the known cooling rates for |
| 59 |
|
those particles obtained via the laser heating experiments. |
| 103 |
|
Values for the interfacial conductance have been determined by a |
| 104 |
|
number of groups for similar nanoparticles and range from a low |
| 105 |
|
$87.5\times 10^{6}$ $(\mathrm{Wm^{-2}K^{-1}})$ to $120\times 10^{6}$ |
| 106 |
< |
$(\mathrm{Wm^{-2}K^{-1}})$.\cite{XXX} |
| 106 |
> |
$(\mathrm{Wm^{-2}K^{-1}})$.\cite{hartlandPrv2007} Plech {\it et al.} reported a value for the interfacial conductance of $G=105\pm 15$ $(\mathrm{Wm^{-2}K^{-1}})$ and |
| 107 |
> |
$G=130\pm 15$ $(\mathrm{Wm^{-2}K^{-1}})$ for Pt nanoparticles.\cite{plech:195423,PhysRevB.66.224301} |
| 108 |
|
|
| 109 |
|
We conducted our simulations at both ends of the range of |
| 110 |
|
experimentally-determined values for the interfacial conductance. |
| 116 |
|
$(\mathrm{Wm^{-2}K^{-1}})$ was used. Based on calculations we have |
| 117 |
|
done using raw data from the Hartland group's thermal half-time |
| 118 |
|
experiments on Au nanospheres, we believe that the true G values are |
| 119 |
< |
closer to the faster regime: $117\times 10^{6}$ |
| 114 |
< |
$(\mathrm{Wm^{-2}K^{-1}})$. |
| 119 |
> |
closer to the faster regime: $117\times 10^{6}$ $(\mathrm{Wm^{-2}K^{-1}})$. |
| 120 |
|
|
| 121 |
+ |
|
| 122 |
|
The rate of cooling for the nanoparticles in a molecular dynamics |
| 123 |
|
simulation can then be tuned by changing the effective solvent |
| 124 |
|
viscosity ($\eta$) until the nanoparticle cooling rate matches the |
