<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Please have a look here:</div><div><br></div><div><a href="http://www.quantum-espresso.org/user_guide/node50.html#SECTION0001110200000000000000">http://www.quantum-espresso.org/user_guide/node50.html#SECTION0001110200000000000000</a></div><div><br></div><div>You can try to play a bit the cutoff or with the FFT mesh size to avoid this.</div><div><br></div><div>HTH</div><div><br></div><div>GS</div><div><br></div><div><div>Il giorno 29/nov/2010, alle ore 13.16, <a href="mailto:giacsport@libero.it">giacsport@libero.it</a> ha scritto:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Dear All,<br> I would like to calculate a structure whose symmetry group is <br>Bmmb. I know that is a orthorombic structure with the ab-plane adopted as a 2D <br>plane.<br>The unit cell is 1 atom of Ti and 2 of oxygen.<br> Cartesian axes<br> site n. atom positions (a_0 units)<br> 1 Ti tau( 1) = ( 0.0000000 0.2500000 0.6800900 )<br> 2 O tau( 2) = ( 0.0000000 0.2500000 0.3832200 )<br> 3 O tau( 3) = ( 0.0000000 0.2500000 0.2180200 )<br><br>I tried setting ibrav = 8, <br> celldm(1)=a (bohr),<br> celldm(2)=b/a,<br> celldm(3)=c/a<br><br>and I got this message in the output<br><br> ortho sub-group = 2* 2 procs<br><br> warning: symmetry operation # 2 not allowed. fractional translation:<br> 0.0000000 0.3862661 0.0000000 in crystal coordinates<br> warning: symmetry operation # 7 not allowed. fractional translation:<br> 0.0000000 0.3862661 0.0000000 in crystal coordinates<br><br>Is the ibrav value not appropriate for the Bmmb space group? Can anybody <br>kindly help me?<br>Very best,<br><br>Giacomo Giorgi,<br>PhD. Tokyo University.<br><br><br>_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>http://www.democritos.it/mailman/listinfo/pw_forum<br></div></blockquote></div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div><span class="Apple-style-span" style="color: rgb(126, 126, 126); font-size: 16px; font-style: italic; "><br class="Apple-interchange-newline">§ Gabriele Sclauzero, EPFL SB ITP CSEA</span></div><div><font class="Apple-style-span" color="#7E7E7E"><i> PH H2 462, Station 3, CH-1015 Lausanne</i></font></div></span>
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