<font size="2">Dear Dimpy Sharma<br>you modify your electrons card as below. i.e add the option electron_maxstep=1000 by default it is 100. If convergence is not achieved in 100 steps then it stops. So put the variable electron_maxstep to a high value say 1000 so that the scf calculation runs till it is converged.<br>
<br>
&ELECTRONS<br>
diagonalization ='david'<br>
mixing_mode = 'plain'<br>
conv_thr = 1.0d-6<br>
mixing_beta = 0.7<br> electron_maxstep=1000<br></font><br><div class="gmail_quote">On Wed, Nov 4, 2009 at 2:35 AM, Stefano de Gironcoli <span dir="ltr"><<a href="mailto:degironc@sissa.it">degironc@sissa.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">have you verified that your crystal structure is reasonable using a<br>
visualizer like xcrysden or similar ?<br>
it appears to me that a couple of atoms are very very close to each other.<br>
stefano<br>
<div><div></div><div class="h5"><br>
Dimpy Sharma wrote:<br>
><br>
> Hi Quantum espresso users,<br>
><br>
> I tired to perform scf calculation but it shows me the following error<br>
> 'convergence NOT achieved after 100 iterations: stopping'<br>
><br>
> However the nscf calculation and projected density of states run<br>
> successfully, why is this so?<br>
><br>
> My input file is as follows<br>
><br>
> &CONTROL<br>
> calculation ='scf'<br>
> restart_mode = 'from_scratch'<br>
> outdir = '/sfiwork/dsharma/PDOSSilane/PDOSsi/si_wfc'<br>
> pseudo_dir = '/sfiwork/dsharma/QE_Pseudos/'<br>
> prefix = 'si'<br>
> tstress = .true.<br>
> tprnfor = .true.<br>
> etot_conv_thr = 1.D-4<br>
> forc_conv_thr = 1.D-3<br>
> nstep = 600<br>
> wf_collect =.true.<br>
> /<br>
> &SYSTEM<br>
> ibrav = 0<br>
> celldm(1) =7.4088<br>
> nat = 6<br>
> ntyp = 1<br>
> ecutwfc = 40<br>
> ecutrho = 160.0<br>
> nbnd = 12<br>
> /<br>
> &ELECTRONS<br>
> diagonalization ='david'<br>
> mixing_mode = 'plain'<br>
> conv_thr = 1.0d-6<br>
> mixing_beta = 0.7<br>
> /<br>
> &IONS<br>
> /<br>
> &CELL<br>
> cell_dynamics='none'<br>
> /<br>
> CELL_PARAMETERS cubic<br>
> 1.000000000 0.000000000 0.000000000<br>
> 0.000000000 2.000000000 0.000000000<br>
> 0.000000000 0.000000000 2.000000000<br>
> ATOMIC_SPECIES<br>
> Si 28.08600 Si.pz-vbc.UPF<br>
> ATOMIC_POSITIONS angstroms<br>
> Si 2.95020 -0.66592 -0.12341<br>
> Si 4.90939 0.61749 0.11358<br>
> Si 0.99475 0.65272 -0.16138<br>
> Si -0.98472 -0.62740 -0.15123<br>
> Si -2.94624 0.68229 -0.12124<br>
> Si -4.89549 -0.61534 0.11905<br>
> K_POINTS automatic<br>
> 4 1 1 0 0 0<br>
><br>
> Can anybody give me any suggestions?<br>
><br>
> Thanks<br>
><br>
> Dimpy<br>
><br>
> Dimpy Sharma,<br>
> PhD<br>
> Electronics Theory Group<br>
> UCC,Cork<br>
> Ireland<br>
><br>
><br>
</div></div>> ------------------------------------------------------------------------<br>
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</blockquote></div><br><br clear="all"><br>-- <br>U.Saibabu<br>PhD student,<br>Deformation mechanisms modeling group,<br>Materials engineering department,<br>IISc Bangalore,<br>India.<br><br>