<br><br><div class="gmail_quote">On Tue, Dec 14, 2010 at 2:19 PM, Justin A. Lemkul <span dir="ltr"><<a href="mailto:jalemkul@vt.edu">jalemkul@vt.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
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Tomy van Batis wrote:<br>
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Dear all<br>
<br>
I have a system consisting of 2 substrates (20 nm distance between them) and inside them there are polymer chains. I would like during my NVT simulations the substrates NOT to move (I suppose I have to put the velocity of the COM of it's substrate to be zero).<br>
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Does anyone know how to do that? <br>
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The simplest way is to just use position restraints. The positions may change very slightly, but not a noticeable amount.<br>
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If you absolutely require no movement at all, use freezegrps in the .mdp file.<br>
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-Justin<br>
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Thanks in advance<br>
Chrysostomos<font color="#888888"><a href="http://www.gromacs.org/Support/Mailing_Lists" target="_blank"></a><br>
</font><br></blockquote></blockquote><div><br>Dear Justin<br><br>I found how to freeze the group that I want, but what I can't find is how to use the position restrains.<br><br>I created just 1 chain. As I can see in my<b> topol.top</b> file it's automatically included the <b>posre.itp</b> file. I inserted in my <b>.mdp</b> file the following line:<br>
define = -DPOSRE<br><br>but after running NVT for few steps I see that the chain is still moving a lot.<br><br>I can't find any example in the manual or in the internet. Can you please tell me what to do?<br><br>Many thanks<br>
<br>Chrysostomos<br></div></div><br>