| 23 |
|
\setlength{\belowcaptionskip}{30 pt} |
| 24 |
|
|
| 25 |
|
%\renewcommand\citemid{\ } % no comma in optional reference note |
| 26 |
< |
\bibpunct{[}{]}{,}{s}{}{;} |
| 27 |
< |
\bibliographystyle{aip} |
| 26 |
> |
\bibpunct{[}{]}{,}{n}{}{;} |
| 27 |
> |
\bibliographystyle{achemso} |
| 28 |
|
|
| 29 |
|
\begin{document} |
| 30 |
|
|
| 104 |
|
this phenomena at the molecular level. Recently, Hase and coworkers |
| 105 |
|
employed Non-Equilibrium Molecular Dynamics (NEMD) simulations to |
| 106 |
|
study thermal transport from hot Au(111) substrate to a self-assembled |
| 107 |
< |
monolayer of alkylthiolate with relatively long chain (8-20 carbon |
| 107 |
> |
monolayer of alkylthiol with relatively long chain (8-20 carbon |
| 108 |
|
atoms)\cite{hase:2010,hase:2011}. However, ensemble averaged |
| 109 |
|
measurements for heat conductance of interfaces between the capping |
| 110 |
|
monolayer on Au and a solvent phase has yet to be studied. |
| 111 |
< |
The relatively low thermal flux through interfaces is |
| 111 |
> |
The comparatively low thermal flux through interfaces is |
| 112 |
|
difficult to measure with Equilibrium MD or forward NEMD simulation |
| 113 |
|
methods. Therefore, the Reverse NEMD (RNEMD) methods would have the |
| 114 |
|
advantage of having this difficult to measure flux known when studying |
| 227 |
|
illustrated in Figure \ref{demoPic}. |
| 228 |
|
|
| 229 |
|
\begin{figure} |
| 230 |
< |
\includegraphics[width=\linewidth]{demoPic} |
| 231 |
< |
\caption{A sample showing how a metal slab has its (111) surface |
| 232 |
< |
covered by capping agent molecules and solvated by hexane.} |
| 230 |
> |
\includegraphics[width=\linewidth]{method} |
| 231 |
> |
\caption{Interfacial conductance can be calculated by applying an |
| 232 |
> |
(unphysical) kinetic energy flux between two slabs, one located |
| 233 |
> |
within the metal and another on the edge of the periodic box. The |
| 234 |
> |
system responds by forming a thermal response or a gradient. In |
| 235 |
> |
bulk liquids, this gradient typically has a single slope, but in |
| 236 |
> |
interfacial systems, there are distinct thermal conductivity |
| 237 |
> |
domains. The interfacial conductance, $G$ is found by measuring the |
| 238 |
> |
temperature gap at the Gibbs dividing surface, or by using second |
| 239 |
> |
derivatives of the thermal profile.} |
| 240 |
|
\label{demoPic} |
| 241 |
|
\end{figure} |
| 242 |
|
|
| 339 |
|
organic solvent molecules in our simulations. |
| 340 |
|
|
| 341 |
|
\begin{figure} |
| 342 |
< |
\includegraphics[width=\linewidth]{demoMol} |
| 343 |
< |
\caption{Denomination of atoms or pseudo-atoms in our simulations: a) |
| 344 |
< |
UA-hexane; b) AA-hexane; c) UA-toluene; d) AA-toluene.} |
| 342 |
> |
\includegraphics[width=\linewidth]{structures} |
| 343 |
> |
\caption{Structures of the capping agent and solvents utilized in |
| 344 |
> |
these simulations. The chemically-distinct sites (a-e) are expanded |
| 345 |
> |
in terms of constituent atoms for both United Atom (UA) and All Atom |
| 346 |
> |
(AA) force fields. Most parameters are from |
| 347 |
> |
Refs. \protect\cite{TraPPE-UA.alkanes,TraPPE-UA.alkylbenzenes} (UA) and |
| 348 |
> |
\protect\cite{OPLSAA} (AA). Cross-interactions with the Au atoms are given |
| 349 |
> |
in Table \ref{MnM}.} |
| 350 |
|
\label{demoMol} |
| 351 |
|
\end{figure} |
| 352 |
|
|
| 387 |
|
(UA or AA) of capping agent can be different from the |
| 388 |
|
solvent. Regardless of model choice, the force field parameters for |
| 389 |
|
interactions between capping agent and solvent can be derived using |
| 390 |
< |
Lorentz-Berthelot Mixing Rule:[EQN'S] |
| 391 |
< |
|
| 390 |
> |
Lorentz-Berthelot Mixing Rule: |
| 391 |
> |
\begin{eqnarray} |
| 392 |
> |
\sigma_{ij} & = & \frac{1}{2} \left(\sigma_{ii} + \sigma_{jj}\right) \\ |
| 393 |
> |
\epsilon_{ij} & = & \sqrt{\epsilon_{ii}\epsilon_{jj}} |
| 394 |
> |
\end{eqnarray} |
| 395 |
|
|
| 396 |
|
To describe the interactions between metal Au and non-metal capping |
| 397 |
|
agent and solvent particles, we refer to an adsorption study of alkyl |
| 420 |
|
\begin{table*} |
| 421 |
|
\begin{minipage}{\linewidth} |
| 422 |
|
\begin{center} |
| 423 |
< |
\caption{Lennard-Jones parameters for Au-non-Metal |
| 424 |
< |
interactions in our simulations.} |
| 425 |
< |
|
| 426 |
< |
\begin{tabular}{ccc} |
| 423 |
> |
\caption{Non-bonded interaction parameters (including cross |
| 424 |
> |
interactions with Au atoms) for both force fields used in this |
| 425 |
> |
work.} |
| 426 |
> |
\begin{tabular}{lllllll} |
| 427 |
|
\hline\hline |
| 428 |
< |
Non-metal atom & $\sigma$ & $\epsilon$ \\ |
| 429 |
< |
(or pseudo-atom) & \AA & kcal/mol \\ |
| 428 |
> |
& Site & $\sigma_{ii}$ & $\epsilon_{ii}$ & $q_i$ & |
| 429 |
> |
$\sigma_{Au-i}$ & $\epsilon_{Au-i}$ \\ |
| 430 |
> |
& & (\AA) & (kcal/mol) & ($e$) & (\AA) & (kcal/mol) \\ |
| 431 |
|
\hline |
| 432 |
< |
S & 2.40 & 8.465 \\ |
| 433 |
< |
CH3 & 3.54 & 0.2146 \\ |
| 434 |
< |
CH2 & 3.54 & 0.1749 \\ |
| 435 |
< |
CT3 & 3.365 & 0.1373 \\ |
| 436 |
< |
CT2 & 3.365 & 0.1373 \\ |
| 437 |
< |
CTT & 3.365 & 0.1373 \\ |
| 438 |
< |
HC & 2.865 & 0.09256 \\ |
| 439 |
< |
CHar & 3.4625 & 0.1680 \\ |
| 440 |
< |
CRar & 3.555 & 0.1604 \\ |
| 441 |
< |
CA & 3.173 & 0.0640 \\ |
| 442 |
< |
HA & 2.746 & 0.0414 \\ |
| 432 |
> |
United Atom (UA) |
| 433 |
> |
&CH3 & 3.75 & 0.1947 & - & 3.54 & 0.2146 \\ |
| 434 |
> |
&CH2 & 3.95 & 0.0914 & - & 3.54 & 0.1749 \\ |
| 435 |
> |
&CHar & 3.695 & 0.1003 & - & 3.4625 & 0.1680 \\ |
| 436 |
> |
&CRar & 3.88 & 0.04173 & - & 3.555 & 0.1604 \\ |
| 437 |
> |
\hline |
| 438 |
> |
All Atom (AA) |
| 439 |
> |
&CT3 & 3.50 & 0.066 & -0.18 & 3.365 & 0.1373 \\ |
| 440 |
> |
&CT2 & 3.50 & 0.066 & -0.12 & 3.365 & 0.1373 \\ |
| 441 |
> |
&CTT & 3.50 & 0.066 & -0.065 & 3.365 & 0.1373 \\ |
| 442 |
> |
&HC & 2.50 & 0.030 & 0.06 & 2.865 & 0.09256 \\ |
| 443 |
> |
&CA & 3.55 & 0.070 & -0.115 & 3.173 & 0.0640 \\ |
| 444 |
> |
&HA & 2.42 & 0.030 & 0.115 & 2.746 & 0.0414 \\ |
| 445 |
> |
\hline |
| 446 |
> |
Both UA and AA & S & 4.45 & 0.25 & - & 2.40 & 8.465 \\ |
| 447 |
|
\hline\hline |
| 448 |
|
\end{tabular} |
| 449 |
|
\label{MnM} |
| 504 |
|
investigations in that we can rely on $G$ measurement with only a |
| 505 |
|
couple $J_z$'s and do not need to test a large series of fluxes. |
| 506 |
|
|
| 507 |
< |
%ADD MORE TO TABLE |
| 507 |
> |
[LOW FLUX, LARGE ERROR] |
| 508 |
|
\begin{table*} |
| 509 |
|
\begin{minipage}{\linewidth} |
| 510 |
|
\begin{center} |
| 513 |
|
interfaces with UA model and different hexane molecule numbers |
| 514 |
|
at different temperatures using a range of energy fluxes.} |
| 515 |
|
|
| 516 |
< |
\begin{tabular}{cccccccc} |
| 516 |
> |
\begin{tabular}{ccccccc} |
| 517 |
|
\hline\hline |
| 518 |
< |
$\langle T\rangle$ & & $L_x$ & $L_y$ & $L_z$ & $J_z$ & |
| 519 |
< |
$G$ & $G^\prime$ \\ |
| 520 |
< |
(K) & $N_{hexane}$ & \multicolumn{3}{c}{(\AA)} & (GW/m$^2$) & |
| 518 |
> |
$\langle T\rangle$ & $N_{hexane}$ & Fixed & $\rho_{hexane}$ & |
| 519 |
> |
$J_z$ & $G$ & $G^\prime$ \\ |
| 520 |
> |
(K) & & $L_x$ \& $L_y$? & (g/cm$^3$) & (GW/m$^2$) & |
| 521 |
|
\multicolumn{2}{c}{(MW/m$^2$/K)} \\ |
| 522 |
|
\hline |
| 523 |
< |
200 & 266 & 29.86 & 25.80 & 113.1 & -0.96 & |
| 524 |
< |
102() & 80.0() \\ |
| 525 |
< |
& 200 & 29.84 & 25.81 & 93.9 & 1.92 & |
| 526 |
< |
129() & 87.3() \\ |
| 527 |
< |
& & 29.84 & 25.81 & 95.3 & 1.93 & |
| 528 |
< |
131() & 77.5() \\ |
| 529 |
< |
& 166 & 29.84 & 25.81 & 85.7 & 0.97 & |
| 530 |
< |
115() & 69.3() \\ |
| 531 |
< |
& & & & & 1.94 & |
| 532 |
< |
125() & 87.1() \\ |
| 533 |
< |
250 & 200 & 29.84 & 25.87 & 106.8 & 0.96 & |
| 534 |
< |
81.8() & 67.0() \\ |
| 535 |
< |
& 166 & 29.87 & 25.84 & 94.8 & 0.98 & |
| 536 |
< |
79.0() & 62.9() \\ |
| 537 |
< |
& & 29.84 & 25.85 & 95.0 & 1.44 & |
| 538 |
< |
76.2() & 64.8() \\ |
| 523 |
> |
200 & 266 & No & 0.672 & -0.96 & 102() & 80.0() \\ |
| 524 |
> |
& 200 & Yes & 0.694 & 1.92 & 129(11) & 87.3(0.3) \\ |
| 525 |
> |
& & Yes & 0.672 & 1.93 & 131(16) & 78(13) \\ |
| 526 |
> |
& & No & 0.688 & 0.96 & 125() & 90.2() \\ |
| 527 |
> |
& & & & 1.91 & 139(10) & 101(10) \\ |
| 528 |
> |
& & & & 2.83 & 141(6) & 89.9(9.8) \\ |
| 529 |
> |
& 166 & Yes & 0.679 & 0.97 & 115(19) & 69(18) \\ |
| 530 |
> |
& & & & 1.94 & 125(9) & 87.1(0.2) \\ |
| 531 |
> |
& & No & 0.681 & 0.97 & 141(30) & 78(22) \\ |
| 532 |
> |
& & & & 1.92 & 138(4) & 98.9(9.5) \\ |
| 533 |
> |
\hline |
| 534 |
> |
250 & 200 & No & 0.560 & 0.96 & 75(10) & 61.8(7.3) \\ |
| 535 |
> |
& & & & -0.95 & 49.4(0.3) & 45.7(2.1) \\ |
| 536 |
> |
& 166 & Yes & 0.570 & 0.98 & 79.0(3.5) & 62.9(3.0) \\ |
| 537 |
> |
& & No & 0.569 & 0.97 & 80.3(0.6) & 67(11) \\ |
| 538 |
> |
& & & & 1.44 & 76.2(5.0) & 64.8(3.8) \\ |
| 539 |
> |
& & & & -0.95 & 56.4(2.5) & 54.4(1.1) \\ |
| 540 |
> |
& & & & -1.85 & 47.8(1.1) & 53.5(1.5) \\ |
| 541 |
|
\hline\hline |
| 542 |
|
\end{tabular} |
| 543 |
|
\label{AuThiolHexaneUA} |
| 568 |
|
important role in the thermal transport process across the interface |
| 569 |
|
in that higher degree of contact could yield increased conductance. |
| 570 |
|
|
| 571 |
< |
[ADD Lxyz AND ERROR ESTIMATE TO TABLE] |
| 571 |
> |
[ADD ERROR ESTIMATE TO TABLE] |
| 572 |
|
\begin{table*} |
| 573 |
|
\begin{minipage}{\linewidth} |
| 574 |
|
\begin{center} |
| 577 |
|
interface at different temperatures using a range of energy |
| 578 |
|
fluxes.} |
| 579 |
|
|
| 580 |
< |
\begin{tabular}{cccc} |
| 580 |
> |
\begin{tabular}{ccccc} |
| 581 |
|
\hline\hline |
| 582 |
< |
$\langle T\rangle$ & $J_z$ & $G$ & $G^\prime$ \\ |
| 583 |
< |
(K) & (GW/m$^2$) & \multicolumn{2}{c}{(MW/m$^2$/K)} \\ |
| 582 |
> |
$\langle T\rangle$ & $\rho_{toluene}$ & $J_z$ & $G$ & $G^\prime$ \\ |
| 583 |
> |
(K) & (g/cm$^3$) & (GW/m$^2$) & \multicolumn{2}{c}{(MW/m$^2$/K)} \\ |
| 584 |
|
\hline |
| 585 |
< |
200 & -1.86 & 180() & 135() \\ |
| 586 |
< |
& 2.15 & 204() & 113() \\ |
| 587 |
< |
& -3.93 & 175() & 114() \\ |
| 588 |
< |
300 & -1.91 & 143() & 125() \\ |
| 589 |
< |
& -4.19 & 134() & 113() \\ |
| 585 |
> |
200 & 0.933 & -1.86 & 180() & 135() \\ |
| 586 |
> |
& & 2.15 & 204() & 113() \\ |
| 587 |
> |
& & -3.93 & 175() & 114() \\ |
| 588 |
> |
\hline |
| 589 |
> |
300 & 0.855 & -1.91 & 143() & 125() \\ |
| 590 |
> |
& & -4.19 & 134() & 113() \\ |
| 591 |
|
\hline\hline |
| 592 |
|
\end{tabular} |
| 593 |
|
\label{AuThiolToluene} |
| 620 |
|
However, when the surface is not completely covered by butanethiols, |
| 621 |
|
the simulated system is more resistent to the reconstruction |
| 622 |
|
above. Our Au-butanethiol/toluene system did not see this phenomena |
| 623 |
< |
even at $\langle T\rangle\sim$300K. The Au(111) surfaces have a 90\% coverage of |
| 624 |
< |
butanethiols and have empty three-fold sites. These empty sites could |
| 625 |
< |
help prevent surface reconstruction in that they provide other means |
| 626 |
< |
of capping agent relaxation. It is observed that butanethiols can |
| 627 |
< |
migrate to their neighbor empty sites during a simulation. Therefore, |
| 628 |
< |
we were able to obtain $G$'s for these interfaces even at a relatively |
| 629 |
< |
high temperature without being affected by surface reconstructions. |
| 623 |
> |
even at $\langle T\rangle\sim$300K. The Au(111) surfaces have a 90\% |
| 624 |
> |
coverage of butanethiols and have empty three-fold sites. These empty |
| 625 |
> |
sites could help prevent surface reconstruction in that they provide |
| 626 |
> |
other means of capping agent relaxation. It is observed that |
| 627 |
> |
butanethiols can migrate to their neighbor empty sites during a |
| 628 |
> |
simulation. Therefore, we were able to obtain $G$'s for these |
| 629 |
> |
interfaces even at a relatively high temperature without being |
| 630 |
> |
affected by surface reconstructions. |
| 631 |
|
|
| 632 |
|
\subsection{Influence of Capping Agent Coverage on $G$} |
| 633 |
|
To investigate the influence of butanethiol coverage on interfacial |
| 703 |
|
its effect to the process of interfacial thermal transport. Thus, one |
| 704 |
|
can see a plateau of $G$ vs. butanethiol coverage in our results. |
| 705 |
|
|
| 706 |
< |
[NEED ERROR ESTIMATE, MAY ALSO PUT J HERE] |
| 707 |
< |
\begin{table*} |
| 708 |
< |
\begin{minipage}{\linewidth} |
| 709 |
< |
\begin{center} |
| 710 |
< |
\caption{Computed interfacial thermal conductivity ($G$) values |
| 711 |
< |
for the Au-butanethiol/solvent interface with various UA |
| 712 |
< |
models and different capping agent coverages at $\langle |
| 713 |
< |
T\rangle\sim$200K using certain energy flux respectively.} |
| 690 |
< |
|
| 691 |
< |
\begin{tabular}{cccc} |
| 692 |
< |
\hline\hline |
| 693 |
< |
Thiol & \multicolumn{3}{c}{$G$(MW/m$^2$/K)} \\ |
| 694 |
< |
coverage (\%) & hexane & hexane(D) & toluene \\ |
| 695 |
< |
\hline |
| 696 |
< |
0.0 & 46.5() & 43.9() & 70.1() \\ |
| 697 |
< |
25.0 & 151() & 153() & 249() \\ |
| 698 |
< |
50.0 & 172() & 182() & 214() \\ |
| 699 |
< |
75.0 & 242() & 229() & 244() \\ |
| 700 |
< |
88.9 & 178() & - & - \\ |
| 701 |
< |
100.0 & 137() & 153() & 187() \\ |
| 702 |
< |
\hline\hline |
| 703 |
< |
\end{tabular} |
| 704 |
< |
\label{tlnUhxnUhxnD} |
| 705 |
< |
\end{center} |
| 706 |
< |
\end{minipage} |
| 707 |
< |
\end{table*} |
| 706 |
> |
\begin{figure} |
| 707 |
> |
\includegraphics[width=\linewidth]{coverage} |
| 708 |
> |
\caption{Comparison of interfacial thermal conductivity ($G$) values |
| 709 |
> |
for the Au-butanethiol/solvent interface with various UA models and |
| 710 |
> |
different capping agent coverages at $\langle T\rangle\sim$200K |
| 711 |
> |
using certain energy flux respectively.} |
| 712 |
> |
\label{coverage} |
| 713 |
> |
\end{figure} |
| 714 |
|
|
| 715 |
|
\subsection{Influence of Chosen Molecule Model on $G$} |
| 716 |
|
[MAY COMBINE W MECHANISM STUDY] |
| 723 |
|
the previous section. Table \ref{modelTest} summarizes the results of |
| 724 |
|
these studies. |
| 725 |
|
|
| 720 |
– |
[MORE DATA; ERROR ESTIMATE] |
| 726 |
|
\begin{table*} |
| 727 |
|
\begin{minipage}{\linewidth} |
| 728 |
|
\begin{center} |
| 730 |
|
\caption{Computed interfacial thermal conductivity ($G$ and |
| 731 |
|
$G^\prime$) values for interfaces using various models for |
| 732 |
|
solvent and capping agent (or without capping agent) at |
| 733 |
< |
$\langle T\rangle\sim$200K.} |
| 733 |
> |
$\langle T\rangle\sim$200K. (D stands for deuterated solvent |
| 734 |
> |
or capping agent molecules; ``Avg.'' denotes results that are |
| 735 |
> |
averages of simulations under different $J_z$'s. Error |
| 736 |
> |
estimates indicated in parenthesis.)} |
| 737 |
|
|
| 738 |
< |
\begin{tabular}{ccccc} |
| 738 |
> |
\begin{tabular}{llccc} |
| 739 |
|
\hline\hline |
| 740 |
|
Butanethiol model & Solvent & $J_z$ & $G$ & $G^\prime$ \\ |
| 741 |
|
(or bare surface) & model & (GW/m$^2$) & |
| 742 |
|
\multicolumn{2}{c}{(MW/m$^2$/K)} \\ |
| 743 |
|
\hline |
| 744 |
< |
UA & AA hexane & 1.94 & 135() & 129() \\ |
| 745 |
< |
& & 2.86 & 126() & 115() \\ |
| 746 |
< |
& AA toluene & 1.89 & 200() & 149() \\ |
| 747 |
< |
AA & UA hexane & 1.94 & 116() & 129() \\ |
| 748 |
< |
& AA hexane & 3.76 & 451() & 378() \\ |
| 749 |
< |
& & 4.71 & 432() & 334() \\ |
| 750 |
< |
& AA toluene & 3.79 & 487() & 290() \\ |
| 751 |
< |
AA(D) & UA hexane & 1.94 & 158() & 172() \\ |
| 752 |
< |
bare & AA hexane & 0.96 & 31.0() & 29.4() \\ |
| 744 |
> |
UA & UA hexane & Avg. & 131(9) & 87(10) \\ |
| 745 |
> |
& UA hexane(D) & 1.95 & 153(5) & 136(13) \\ |
| 746 |
> |
& AA hexane & Avg. & 131(6) & 122(10) \\ |
| 747 |
> |
& UA toluene & 1.96 & 187(16) & 151(11) \\ |
| 748 |
> |
& AA toluene & 1.89 & 200(36) & 149(53) \\ |
| 749 |
> |
\hline |
| 750 |
> |
AA & UA hexane & 1.94 & 116(9) & 129(8) \\ |
| 751 |
> |
& AA hexane & Avg. & 442(14) & 356(31) \\ |
| 752 |
> |
& AA hexane(D) & 1.93 & 222(12) & 234(54) \\ |
| 753 |
> |
& UA toluene & 1.98 & 125(25) & 97(60) \\ |
| 754 |
> |
& AA toluene & 3.79 & 487(56) & 290(42) \\ |
| 755 |
> |
\hline |
| 756 |
> |
AA(D) & UA hexane & 1.94 & 158(25) & 172(4) \\ |
| 757 |
> |
& AA hexane & 1.92 & 243(29) & 191(11) \\ |
| 758 |
> |
& AA toluene & 1.93 & 364(36) & 322(67) \\ |
| 759 |
> |
\hline |
| 760 |
> |
bare & UA hexane & Avg. & 46.5(3.2) & 49.4(4.5) \\ |
| 761 |
> |
& UA hexane(D) & 0.98 & 43.9(4.6) & 43.0(2.0) \\ |
| 762 |
> |
& AA hexane & 0.96 & 31.0(1.4) & 29.4(1.3) \\ |
| 763 |
> |
& UA toluene & 1.99 & 70.1(1.3) & 65.8(0.5) \\ |
| 764 |
|
\hline\hline |
| 765 |
|
\end{tabular} |
| 766 |
|
\label{modelTest} |
| 797 |
|
|
| 798 |
|
However, for Au-butanethiol/toluene interfaces, having the AA |
| 799 |
|
butanethiol deuterated did not yield a significant change in the |
| 800 |
< |
measurement results. |
| 801 |
< |
. , so extra degrees of freedom |
| 802 |
< |
such as the C-H vibrations could enhance heat exchange between these |
| 803 |
< |
two phases and result in a much higher conductivity. |
| 800 |
> |
measurement results. Compared to the C-H vibrational overlap between |
| 801 |
> |
hexane and butanethiol, both of which have alkyl chains, that overlap |
| 802 |
> |
between toluene and butanethiol is not so significant and thus does |
| 803 |
> |
not have as much contribution to the ``Intramolecular Vibration |
| 804 |
> |
Redistribution''[CITE HASE]. Conversely, extra degrees of freedom such |
| 805 |
> |
as the C-H vibrations could yield higher heat exchange rate between |
| 806 |
> |
these two phases and result in a much higher conductivity. |
| 807 |
|
|
| 786 |
– |
|
| 808 |
|
Although the QSC model for Au is known to predict an overly low value |
| 809 |
< |
for bulk metal gold conductivity[CITE NIVSRNEMD], our computational |
| 809 |
> |
for bulk metal gold conductivity\cite{kuang:164101}, our computational |
| 810 |
|
results for $G$ and $G^\prime$ do not seem to be affected by this |
| 811 |
< |
drawback of the model for metal. Instead, the modeling of interfacial |
| 812 |
< |
thermal transport behavior relies mainly on an accurate description of |
| 813 |
< |
the interactions between components occupying the interfaces. |
| 811 |
> |
drawback of the model for metal. Instead, our results suggest that the |
| 812 |
> |
modeling of interfacial thermal transport behavior relies mainly on |
| 813 |
> |
the accuracy of the interaction descriptions between components |
| 814 |
> |
occupying the interfaces. |
| 815 |
|
|
| 816 |
|
\subsection{Mechanism of Interfacial Thermal Conductance Enhancement |
| 817 |
|
by Capping Agent} |
| 827 |
|
the velocity auto-correlation functions, which is used to construct a |
| 828 |
|
power spectrum via a Fourier transform. |
| 829 |
|
|
| 830 |
+ |
[MAY RELATE TO HASE'S] |
| 831 |
|
The gold surfaces covered by |
| 832 |
|
butanethiol molecules, compared to bare gold surfaces, exhibit an |
| 833 |
|
additional peak observed at a frequency of $\sim$170cm$^{-1}$, which |
| 840 |
|
combination of these two effects produces the drastic interfacial |
| 841 |
|
thermal conductance enhancement in the all-atom model. |
| 842 |
|
|
| 843 |
< |
[MAY NEED TO CONVERT TO JPEG] |
| 843 |
> |
[REDO. MAY NEED TO CONVERT TO JPEG] |
| 844 |
|
\begin{figure} |
| 845 |
|
\includegraphics[width=\linewidth]{vibration} |
| 846 |
|
\caption{Vibrational spectra obtained for gold in different |
