From: hackbard Date: Thu, 14 Sep 2006 15:27:55 +0000 (+0000) Subject: hmmm ... X-Git-Url: https://hackdaworld.org/gitweb/?a=commitdiff_plain;h=08f9c1435f017ec1f9202e0632cfb8989613e308;p=lectures%2Flatex.git hmmm ... --- diff --git a/posic/thesis/basics.tex b/posic/thesis/basics.tex index 6d292e8..d3c91aa 100644 --- a/posic/thesis/basics.tex +++ b/posic/thesis/basics.tex @@ -190,14 +190,14 @@ F_n^i & = & - \frac{\partial}{\partial x_n} \sum_{j \neq i} V_{ij} \nonumber\\ The cutoff function $f_C$ derivated with repect to $x^i_n$ is \begin{equation} \partial_{x^i_n} f_C(r_{ij}) = - \frac{1}{2} \sin \Big( \pi (r_{ij} - R_{ij}) / (S_{ij} - R_{ij}) \Big) \frac{\pi x^i_n}{(S_{ij} - R_{ij}) r_{ij}} + - \frac{1}{2} \sin \Big( \pi (r_{ij} - R_{ij}) / (S_{ij} - R_{ij}) \Big) \frac{\pi x^i_n}{(S_{ij} - R_{ij}) r_{ij}} \label{eq:d_cutoff} \end{equation} for $R_{ij} < r_{ij} < S_{ij}$ and otherwise zero. The derivations of the repulsive and attractive part are: \begin{eqnarray} -\partial_{x_n^i} f_R(r_{ij}) & = & - \lambda_{ij} A_{ij} \exp (-\lambda_{ij} r_{ij})\\ -\partial_{x_n^i} f_A(r_{ij}) & = & \mu_{ij} B_{ij} \exp (-\mu_{ij} r_{ij}) \textrm{ .} +\partial_{x_n^i} f_R(r_{ij}) & = & - \lambda_{ij} \frac{x_n^i - x_n^j}{r_{ij}} A_{ij} \exp (-\lambda_{ij} r_{ij})\\ +\partial_{x_n^i} f_A(r_{ij}) & = & \mu_{ij} \frac{x_n^i - x_n^j}{r_{ij}} B_{ij} \exp (-\mu_{ij} r_{ij}) \textrm{ .} \end{eqnarray} The angle $\theta_{ijk}$ can be expressed by the atom distances with the law of cosines: \begin{eqnarray}