| 405 |
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\label{fig:structures} |
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|
\end{figure} |
| 407 |
|
|
| 408 |
< |
The Au-Au interactions in metal lattice slab is described by the |
| 408 |
> |
The Au-Au interactions in the metal lattice slab are described by the |
| 409 |
|
quantum Sutton-Chen (QSC) formulation.\cite{PhysRevB.59.3527} The QSC |
| 410 |
|
potentials include zero-point quantum corrections and are |
| 411 |
|
reparametrized for accurate surface energies compared to the |
| 487 |
|
\subsection{Effect of Mixed Chain Lengths} |
| 488 |
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|
| 489 |
|
Previous work demonstrated that for butanethiolate monolayers on a Au(111) surface, the interfacial conductance was a non-monotonic function of the percent coverage. This is believed to be due to enhanced solvent-thiolate coupling through greater penetration of solvent molecules into the thiolate layer. At lower coverages, hexane solvent can more easily line up lengthwise with the thiolate tails by fitting into gaps between the thiolates. However, a side effect of low coverages is surface aggregation of the thiolates. To simulate the effect of low coverages while preventing aggregation we maintain 100\% thiolate coverage while varying the proportions of short (butanethiolate, n = 4) and long (decanethiolate, n = 10 or dodecanethiolate, n = 12). In systems where there is a mix of short and long chain thiolates, interfacial conductance is a non-monotonic function of the percent of long chains. The depth of the gaps between the long chains is $n_{long} - n_{short}$, which has implications for the ability of the hexane solvent to fill in the gaps between the long chains. |
| 490 |
+ |
|
| 491 |
+ |
\begin{figure} |
| 492 |
+ |
\includegraphics[width=\linewidth]{figures/Gstacks} |
| 493 |
+ |
\caption{} |
| 494 |
+ |
\label{fig:Gstacks} |
| 495 |
+ |
\end{figure} |
| 496 |
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|
| 497 |
|
\subsubsection{Butanethiolate/Decanethiolate} |
| 498 |
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Mixtures of butanethiolate/decanethiolate (n = 4, 10) have a peak interfacial condutance for 25\%/75\% short/long chains. |
| 548 |
|
the rate at which solvent molecules entangled in the thiolate layer |
| 549 |
|
can escape into the bulk. As $k_{escape} \rightarrow \infty$, the |
| 550 |
|
solvent has become permanently trapped in the thiolate layer. In |
| 551 |
< |
figure \ref{figure:res} we show that interfacial solvent mobility |
| 551 |
> |
figure \ref{figure:Gstack} we show that interfacial solvent mobility |
| 552 |
|
decreases as the percentage of long thiolate chains increases. |
| 553 |
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|
| 554 |
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|
