Dear Yang <br>you can do relaxation with&nbsp; calculation&nbsp; = &quot;relax&quot;, and<br><br>&nbsp;&amp;electrons<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; conv_thr = 1.d-6,<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; startingwfc = &#39;atomic&#39;,<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; mixing_beta = 0.3,<br>&nbsp;&nbsp; diagonalization = &#39;david_overlap&#39;,<br>
/<br>&nbsp;&amp;ions<br>&nbsp;ion_dynamics = &#39;damp&#39;,<br>&nbsp; pot_extrapolation = &quot;second_order&quot;,<br>&nbsp; wfc_extrapolation = &quot;second_order&quot;,<br><br>&nbsp;and also you can fix positions with &#39;0&#39; after any ATOMIC_POSITIONS<br>
bye Mansoureh<br><br><br><br><div class="gmail_quote">On Wed, Jul 9, 2008 at 7:22 PM, ΛοΡτ &lt;<a href="mailto:sunyang198498@gmail.com">sunyang198498@gmail.com</a>&gt; wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi!<br>
how could I relax the atoms position without changing the cell parameters<br>
say, if i have a simple cubic cell with each point having a benzene<br>
structure. How could I relax the benzene&#39;s atoms, say, hydrogen and<br>
carbon with the fixed edge size within the simple cubic cell.<br>
<br>
Thank you,<br>
<br>
Yang<br>
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