X-Git-Url: https://hackdaworld.org/gitweb/?p=lectures%2Flatex.git;a=blobdiff_plain;f=posic%2Fthesis%2Fd_tersoff.tex;h=84929638f3fd7f8a656fd7d51656dd426ef90f6e;hp=9a5e76b8694259247af052e36bc5550010d780fc;hb=dfeb4ccb085d878b5639dcaea7fcb7fcdc5248ad;hpb=5c140338a7cab0ea646c8c387df2d9bf6df6f8af diff --git a/posic/thesis/d_tersoff.tex b/posic/thesis/d_tersoff.tex index 9a5e76b..8492963 100644 --- a/posic/thesis/d_tersoff.tex +++ b/posic/thesis/d_tersoff.tex @@ -38,9 +38,9 @@ For a three body potential, if $V_{ij}$ is not equal to $V_{ji}$, the derivative \begin{equation} \nabla_{{\bf r}_i} E = \frac{1}{2} \big[ \sum_j ( \nabla_{{\bf r}_i} V_{ij} + \nabla_{{\bf r}_i} V_{ji} ) + \sum_k \sum_j \nabla_{{\bf r}_i} V_{jk} \big] \textrm{ .} \end{equation} -In the following all the necessary derivatives to calculate $\nabla_{{\bf r}_i} E$ are done. +In the following all the necessary derivatives to calculate $\nabla_{{\bf r}_i} E$ are written down. - \section{Derivative of $V_{ij}$ with respect to ${\bf r}_i$} + \section[Derivative of $V_{ij}$ with respect to ${r}_i$]{\boldmath Derivative of $V_{ij}$ with respect to ${\bf r}_i$} \begin{eqnarray} \nabla_{{\bf r}_i} V_{ij} & = & \nabla_{{\bf r}_i} f_C(r_{ij}) \big[ f_R(r_{ij}) + b_{ij} f_A(r_{ij}) \big] + \nonumber \\ @@ -67,7 +67,7 @@ In the following all the necessary derivatives to calculate $\nabla_{{\bf r}_i} & = & \Big[ \frac{\cos\theta_{ijk}}{r_{ij}^2} - \frac{1}{r_{ij} r_{ik}} \Big] {\bf r}_{ij} + \Big[ \frac{\cos\theta_{ijk}}{r_{ik}^2} - \frac{1}{r_{ij} r_{ik}} \Big] {\bf r}_{ik} \end{eqnarray} - \section{Derivative of $V_{ji}$ with respect to ${\bf r}_i$} + \section[Derivative of $V_{ji}$ with respect to ${r}_i$]{\boldmath Derivative of $V_{ji}$ with respect to ${\bf r}_i$} \begin{eqnarray} \nabla_{{\bf r}_i} V_{ji} & = & \nabla_{{\bf r}_i} f_C(r_{ji}) \big[ f_R(r_{ji}) + b_{ji} f_A(r_{ji}) \big] + \nonumber \\ @@ -95,7 +95,7 @@ In the following all the necessary derivatives to calculate $\nabla_{{\bf r}_i} & = & \frac{1}{r_{ji} r_{jk}} {\bf r}_{jk} - \frac{\cos\theta_{jik}}{r_{ji}^2} {\bf r}_{ji} \end{eqnarray} - \section{Derivative of $V_{jk}$ with respect to ${\bf r}_i$} + \section[Derivative of $V_{jk}$ with respect to ${r}_i$]{\boldmath Derivative of $V_{jk}$ with respect to ${\bf r}_i$} \begin{eqnarray} \nabla_{{\bf r}_i} V_{jk} & = & f_C(r_{jk}) f_A(r_{jk}) \nabla_{{\bf r}_i} b_{jk} \\ @@ -128,7 +128,7 @@ This poses a more convenient method to obtain the forces keeping in mind that all the necessary force contributions for atom $i$ are calculated and added in subsequent loops. -\subsection{Derivative of $V_{ij}$ with respect to ${\bf r}_j$} +\subsection[Derivative of $V_{ij}$ with respect to ${r}_j$]{\boldmath Derivative of $V_{ij}$ with respect to ${\bf r}_j$} \begin{eqnarray} \nabla_{{\bf r}_j} V_{ij} & = & @@ -155,7 +155,7 @@ The contribution of the bond order term is given by: \frac{\cos\theta_{ijk}}{r_{ij}^2}{\bf r}_{ij} \end{eqnarray} -\subsection{Derivative of $V_{ij}$ with respect to ${\bf r}_k$} +\subsection[Derivative of $V_{ij}$ with respect to ${r}_k$]{\boldmath Derivative of $V_{ij}$ with respect to ${\bf r}_k$} The derivative of $V_{ij}$ with respect to ${\bf r}_k$ just consists of the single term