Please have a look here: http://www.quantum-espresso.org/user_guide/node50.html#SECTION0001110200000000000000
You can try to play a bit the cutoff or with the FFT mesh size to avoid this. HTH GS Il giorno 29/nov/2010, alle ore 13.16, giacsport at libero.it ha scritto: > Dear All, > I would like to calculate a structure whose symmetry group is > Bmmb. I know that is a orthorombic structure with the ab-plane adopted as a > 2D > plane. > The unit cell is 1 atom of Ti and 2 of oxygen. > Cartesian axes > site n. atom positions (a_0 units) > 1 Ti tau( 1) = ( 0.0000000 0.2500000 0.6800900 ) > 2 O tau( 2) = ( 0.0000000 0.2500000 0.3832200 ) > 3 O tau( 3) = ( 0.0000000 0.2500000 0.2180200 ) > > I tried setting ibrav = 8, > celldm(1)=a (bohr), > celldm(2)=b/a, > celldm(3)=c/a > > and I got this message in the output > > ortho sub-group = 2* 2 procs > > warning: symmetry operation # 2 not allowed. fractional translation: > 0.0000000 0.3862661 0.0000000 in crystal coordinates > warning: symmetry operation # 7 not allowed. fractional translation: > 0.0000000 0.3862661 0.0000000 in crystal coordinates > > Is the ibrav value not appropriate for the Bmmb space group? Can anybody > kindly help me? > Very best, > > Giacomo Giorgi, > PhD. Tokyo University. > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum ? Gabriele Sclauzero, EPFL SB ITP CSEA PH H2 462, Station 3, CH-1015 Lausanne -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20101129/0b9a641c/attachment.htm
