--- trunk/COonPt/firstTry.tex 2013/03/12 21:33:15 3873 +++ trunk/COonPt/firstTry.tex 2013/03/13 14:57:09 3874 @@ -364,8 +364,8 @@ The different bulk melting temperatures (1337~K for Au 1200~K were performed to confirm the relative stability of the surfaces without a CO overlayer. -The different bulk melting temperatures (1337~K for Au -and 2045~K for Pt) suggest that any possible reconstruction should happen at +The different bulk melting temperatures (1337~K for Au\cite{Au:melting} +and 2045~K for Pt\cite{Pt:melting}) suggest that any possible reconstruction should happen at different temperatures for the two metals. The bare Au and Pt surfaces were initially run in the canonical (NVT) ensemble at 800~K and 1000~K respectively for 100 ps. The two surfaces were relatively stable at these @@ -419,13 +419,13 @@ repulsion exists because the entropy of the step-edges original (557) lattice. Previous work by Williams et al.\cite{Williams:1991, Williams:1994} highlights the repulsion that exists between step-edges even when no direct interactions are present in the system. This -repulsion exists because the entropy of the step-edges is constrained +repulsion arises because the entropy of the step-edges is constrained, since step-edge crossing is not allowed. This entropic repulsion does not completely define the interactions between steps, which is why some surfaces will undergo step coalescence, where additional attractive interactions can overcome the -repulsion\cite{Williams:1991} and others will not. The presence -of adsorbates can affect these step interactions, potentially +repulsion\cite{Williams:1991} and others will not. The presence and concentration +of adsorbates, as shown in this work, can affect these step interactions, potentially leading to a new surface structure as the thermodynamic minimum. \subsubsection{Double layers} @@ -442,8 +442,8 @@ doubling seen by Tao et al. within the time scales stu effect that adsorbate coverage has on edge breakup and on the surface diffusion of metal adatoms. While both systems displayed step-edge wandering, only the 50\% Pt surface underwent the -doubling seen by Tao et al. within the time scales studied here. -Over longer periods (150~ns) two more double layers formed +doubling seen by Tao et al.\cite{Tao:2010} within the time scales studied here. +Over longer periods, (150~ns) two more double layers formed on this interface. Although double layer formation did not occur in the other Pt systems, they show more step-wandering and general roughening compared to their Au counterparts. The @@ -465,7 +465,7 @@ $\sim$70 s/image provides an upper bound for the time of ignoring the dynamics of the system. Previous experimental work by Pearl and Sibener\cite{Pearl}, using STM, has been able to capture the coalescing of steps on Ni(977). The time scale of the image acquisition, -$\sim$70 s/image provides an upper bound for the time required for +$\sim$70~s/image provides an upper bound for the time required for the doubling to occur. In this section we give data on dynamic and transport properties, e.g. diffusion, layer formation time, etc. @@ -642,7 +642,7 @@ are displayed in Table \ref{tab:energies} with the cor of Pt atoms was then examined to determine possible barriers. Because the movement was forced along a pre-defined reaction coordinate that may differ from the true minimum of this path, only the beginning and ending energies -are displayed in Table \ref{tab:energies} with the corresponding beginning and ending reaction coordinates in Figure \ref{fig:lambdaTable}. These values suggest that the presence of CO at suitable +are displayed in Table \ref{tab:rxcoord} with the corresponding beginning and ending reaction coordinates in Figure \ref{fig:lambdaTable}. These values suggest that the presence of CO at suitable locations can lead to lowered barriers for Pt breaking apart from the step-edge. Additionally, as highlighted in Figure \ref{fig:lambda}, the presence of CO makes the burrowing and lifting of adatoms favorable, whereas without CO, the process is neutral @@ -666,8 +666,28 @@ in terms of energetics. \caption{} \label{fig:lambdaTable} \end{figure} + + +\begin{table}[H] +\caption{} +\centering +\begin{tabular}{| c || c | c | c | c |} +\hline +\textbf{System} & 0.5~\AA & 2~\AA & 4~\AA & 6~\AA \\ +\hline +A & 6.38 & 38.34 & 44.65 & 47.60 \\ +B & -20.72 & 0.67 & 17.33 & 24.28 \\ +C & 4.92 & 27.02 & 41.05 & 47.43 \\ +D & -16.97 & 21.21 & 35.87 & 40.93 \\ +E & 5.92 & 30.96 & 43.69 & 49.23 \\ +F & 8.53 & 46.23 & 53.98 & 65.55 \\ +\hline +\end{tabular} +\label{tab:rxcoord} +\end{table} + \subsection{Diffusion} The diffusion parallel to the step-edge tends to be much larger than that perpendicular to the step-edge. The dynamic