--- trunk/nonperiodicVSS/nonperiodicVSS.tex 2014/01/08 22:24:46 3992 +++ trunk/nonperiodicVSS/nonperiodicVSS.tex 2014/01/14 19:47:08 3994 @@ -88,15 +88,15 @@ boundary between materials. is often unclear what shape of gradient should be imposed at the boundary between materials. -% \begin{figure} -% \includegraphics[width=\linewidth]{figures/VSS} -% \caption{Schematics of periodic (left) and non-periodic (right) -% Velocity Shearing and Scaling RNEMD. A kinetic energy or momentum -% flux is applied from region B to region A. Thermal gradients are -% depicted by a color gradient. Linear or angular velocity gradients -% are shown as arrows.} -% \label{fig:VSS} -% \end{figure} +\begin{figure} +\includegraphics[width=\linewidth]{figures/npVSS} +\caption{Schematics of periodic (left) and non-periodic (right) + Velocity Shearing and Scaling RNEMD. A kinetic energy or momentum + flux is applied from region B to region A. Thermal gradients are + depicted by a color gradient. Linear or angular velocity gradients + are shown as arrows.} +\label{fig:VSS} +\end{figure} Reverse Non-Equilibrium Molecular Dynamics (RNEMD) methods impose an unphysical {\it flux} between different regions or ``slabs'' of the @@ -132,7 +132,7 @@ concentric spheres (as in figure \ref{fig:VSS}), or on We have extended the VSS method for use in {\it non-periodic} simulations, in which the ``slabs'' have been generalized to two separated regions of space. These regions could be defined as -concentric spheres (as in figure \ref{fig:VSS}), or one of the regions +concentric spheres (as in figure \ref{fig:npVSS}), or one of the regions can be defined in terms of a dynamically changing ``hull'' comprising the surface atoms of the cluster. This latter definition is identical to the hull used in the Langevin Hull algorithm. @@ -426,9 +426,9 @@ Table \ref{table:couple} shows the calculated rotation Table \ref{table:couple} shows the calculated rotational friction coefficients $\Xi^{rr}$ for spherical gold nanoparticles and a prolate ellipsoidal gold nanorod in TraPPE-UA hexane. An angular momentum flux was applied between the A and B regions defined as the gold structure and hexane molecules beyond a certain radius, respectively. The resulting angular velocity gradient causes the gold structure to rotate about the prescribed axis. \begin{longtable}{lcccc} -\caption{Comparison of rotational friction coefficients under ideal ``stick'' conditions ($\Xi^{rr}_{stick}$) calculated via Stokes' and Perrin's laws and effective rotational friction coefficients ($\Xi^{rr}_{\mathit{eff}}$) of gold nanostructures solvated in TraPPE-UA hexane at 230 K. The ellipsoid is oriented with the long axis along the $z$ direction.} +\caption{Comparison of rotational friction coefficients under ideal ``stick'' conditions ($\Xi^{rr}_{\mathit{stick}}$) calculated via Stokes' and Perrin's laws and effective rotational friction coefficients ($\Xi^{rr}_{\mathit{eff}}$) of gold nanostructures solvated in TraPPE-UA hexane at 230 K. The ellipsoid is oriented with the long axis along the $z$ direction.} \\ \hline \hline -{Structure} & {Axis of Rotation} & {$\Xi^{rr}_{stick}$} & {$\Xi^{rr}_{\mathit{eff}}$} & {$\Xi^{rr}_{\mathit{eff}}$ / $\Xi^{rr}_{stick}$}\\ +{Structure} & {Axis of Rotation} & {$\Xi^{rr}_{\mathit{stick}}$} & {$\Xi^{rr}_{\mathit{eff}}$} & {$\Xi^{rr}_{\mathit{eff}}$ / $\Xi^{rr}_{\mathit{stick}}$}\\ {} & {} & {\small(amu A$^2$ fs$^{-1}$)} & {\small(amu A$^2$ fs$^{-1}$)} & \\ \hline Sphere (r = 20 \AA) & {$x = y = z$} & {3314} & {2386} & {0.720}\\ Sphere (r = 30 \AA) & {$x = y = z$} & {11749} & {8415} & {0.716}\\ @@ -439,6 +439,8 @@ Prolate Ellipsoid & {$z$} & {1993} & {1590} & {0.798}\ \label{table:couple} \end{longtable} + + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % **DISCUSSION** %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%