<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 03 Jul 2015, at 10:21, Geng Sun <<a href="mailto:sungen...@gmail.com" class="">sungen...@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="">Teo,</div><div class=""><br class=""></div><div class=""> The substrate for my model is Al2O3, which is ionic compound. This can be described by some classical force field.</div><div class=""> like</div><div class=""> <a href="http://dx.doi.org/10.1063/1.4832695" rel="external" class="externallink">http://dx.doi.org/10.1063/1.4832695</a></div><div class=""> or more general Tersoff style potentials</div><div class=""><br class=""></div><div class=""> I am a newbie using QMMM in CP2K. Two things confused me:<br class=""></div><div class=""><br class=""></div></div></div></blockquote><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""> 1) What kinds of classical force field could be used in CP2K,</div></div></div></blockquote><div><br class=""></div><div>You can use a multitude of classical potential. From third parties like AMBER and CHARMM to self-made potentials (including many-bodies, etc..). Have a look at the examples in the Fist regtest directory</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""> 2) What's the different of <a href="http://manual.cp2k.org/cp2k-2_6-branch/CP2K_INPUT.html" style="font-family: monospace; text-transform: uppercase;" class="">CP2K_INPUT</a><span style="font-family: monospace; text-transform: uppercase;" class=""> / </span><a href="http://manual.cp2k.org/cp2k-2_6-branch/CP2K_INPUT/FORCE_EVAL.html" style="font-family: monospace; text-transform: uppercase;" class="">FORCE_EVAL</a><span style="font-family: monospace; text-transform: uppercase;" class=""> / </span><a href="http://manual.cp2k.org/cp2k-2_6-branch/CP2K_INPUT/FORCE_EVAL/MIXED.html" style="font-family: monospace; text-transform: uppercase;" class="">MIXED</a>, and <a href="http://manual.cp2k.org/cp2k-2_6-branch/CP2K_INPUT.html" style="font-family: monospace; text-transform: uppercase;" class="">CP2K_INPUT</a><span style="font-family: monospace; text-transform: uppercase;" class=""> / </span><a href="http://manual.cp2k.org/cp2k-2_6-branch/CP2K_INPUT/FORCE_EVAL.html" style="font-family: monospace; text-transform: uppercase;" class="">FORCE_EVAL</a><span style="font-family: monospace; text-transform: uppercase;" class=""> / </span><a href="http://manual.cp2k.org/cp2k-2_6-branch/CP2K_INPUT/FORCE_EVAL/QMMM.html" style="font-family: monospace; text-transform: uppercase;" class="">QMMM</a></div><div class=""> which one should I use ?</div></div></div></blockquote><div>MIXED allows you to mix different Hamiltonians (total energy of your system is the sum of the terms of the different Hamiltonians). The best you can do is an ONIOM scheme (see literature).</div><div><br class=""></div><div>If you want electronic coupling (between classical and quantum), you need to use the QMMM. Total energy here is still some of the classical + quantum but moreover you have also a QMMM term. So this is the one you should be using.</div><div><br class=""></div><div>Teo</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""></div><div class=""> Thanks again !</div><div class=""><br class=""></div><div class=""> Geng</div><br class=""><br class="">在 2015年7月3日星期五 UTC+8下午2:47:40，Teo写道：<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div style="word-wrap:break-word" class="">Hello,<div class=""><br class=""></div><div class="">as long as you have a sufficiently good force-field for the slab you can do that.</div><div class="">In your specific case, it should be enough to have parameters that capture most of the interaction within that material.</div><div class=""><br class=""></div><div class="">Did you search in literature for available classical force-field for your slab material ?</div><div class=""><br class=""></div><div class="">Teo</div><div class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On 03 Jul 2015, at 07:35, Geng Sun <<a href="javascript:" target="_blank" gdf-obfuscated-mailto="oAjLV_rojm0J" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;" class="">sung...@gmail.com</a>> wrote:</div><br class=""><div class=""><div dir="ltr" class="">Hello everyone <div class=""><br class=""></div><div class=""> I want to study supported metal cluster using molecular dynamics.</div><div class=""><br class=""></div><div class=""> Here, the substrate is represented by a slab which is metal oxide, and the metal cluster is put on the surface of the slab.</div><div class=""><br class=""></div><div class=""> I want to use the QMMM to reduce the computational cost by using the force field to describe the interaction of the bottom layers of slab model. The upper layers of slab</div><div class=""> and the metal atoms are left for DFT.</div><div class=""><br class=""></div><div class=""> Is that possible for CP2K to do the QMMM simulation in such case? If so, what is the most relevant parameters. </div><div class=""><br class=""></div><div class=""> Thanks in advance !</div><div class=""><br class=""></div><div class=""> Geng Sun</div><div class=""> </div></div><div class=""><br class=""></div> -- <br class=""> You received this message because you are subscribed to the Google Groups "cp2k" group.<br class=""> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="oAjLV_rojm0J" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;" class="">cp2k+uns...@googlegroups.<wbr class="">com</a>.<br class=""> To post to this group, send email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="oAjLV_rojm0J" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;" class="">cp...@googlegroups.com</a>.<br class=""> Visit this group at <a href="http://groups.google.com/group/cp2k" target="_blank" rel="nofollow" onmousedown="this.href='http://groups.google.com/group/cp2k';return true;" onclick="this.href='http://groups.google.com/group/cp2k';return true;" class="">http://groups.google.com/<wbr class="">group/cp2k</a>.<br class=""> For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/d/optout';return true;" onclick="this.href='https://groups.google.com/d/optout';return true;" class="">https://groups.google.com/d/<wbr class="">optout</a>.<br class=""> </div></blockquote></div><br class=""></div></div></blockquote></div><div class=""><br class="webkit-block-placeholder"></div> -- <br class=""> You received this message because you are subscribed to the Google Groups "cp2k" group.<br class=""> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+uns...@googlegroups.com" class="">cp2k+uns...@googlegroups.com</a>.<br class=""> To post to this group, send email to <a href="mailto:cp...@googlegroups.com" class="">cp...@googlegroups.com</a>.<br class=""> Visit this group at <a href="http://groups.google.com/group/cp2k" class="">http://groups.google.com/group/cp2k</a>.<br class=""> For more options, visit <a href="https://groups.google.com/d/optout" class="">https://groups.google.com/d/optout</a>.<br class=""> </div></blockquote></div><br class=""></body></html>