<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt">Dear Olga,<br><br>I could not reproduce the error you report using different pw.x versions. <br>They finished by the error message (QE 4.2, compiler gfortran on Ubuntu 9.4 on my laptop, serial):<br> <br> from scale_h : error # 1<br> Not enough space allocated for radial FFT: try restarting with a larger cell_factor.<br><br>Usually,
that means unreasonable lattice parameters. Say, one of them is much
larger than expected. In fact, this turned out to be dependent on
ecutwfc and pseudopotential type. The error persists for norm-conserving
type pseudo you used. But using US pseudo for C, and the cutoff energy
30Ry (360 for ecutrho) , no
problem arises. <br>Besides, for Norm-conserving type pseudo for C 18Ry seems to be
extremely low. <br>You can play around ecutwfc, upscale and cell_factor parameters. <br><br>If you like, you can fix c-axis, do relax, and using a set of c-axis parameter find the minimum. <br> <br>Last, if you study a graphene sheet why you used 6 6 6? The correct one seems to be 6 6 1.<br><br>Bests,<br>Eyvaz.<div> </div>-------------------------------------------------------------------<br>Prof. Eyvaz Isaev, <br>Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden <br>Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, <br>isaev@ifm.liu.se, eyvaz_isaev@yahoo.com<div><br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Olga Sedelnikova
<o.sedelnikova@gmail.com><br><b><span style="font-weight: bold;">To:</span></b> pw_forum@pwscf.org<br><b><span style="font-weight: bold;">Sent:</span></b> Tue, July 27, 2010 12:42:53 PM<br><b><span style="font-weight: bold;">Subject:</span></b> [Pw_forum] problem with vc-relax<br></font><br>
<div><font color="#330099"><font size="2"><font face="comic sans ms,sans-serif">Dear All,</font></font></font></div>
<div><font color="#330099"><font size="2"><font face="comic sans ms,sans-serif">I have a problem with 'vc-relax' option for graphene. </font></font></font><font color="#330099"><font size="2"><font face="comic sans ms,sans-serif">I have used david and cg diagonalization proceedures, different types of smearing and ion and cell dynamics but all calculations were crashed. </font></font></font></div>
<div><font color="#330099"><font size="2"><font face="comic sans ms,sans-serif">One of my input file:</font></font></font></div>
<div><font color="#330099" face="Comic Sans MS"></font> </div>
<div><font color="#330099" face="Comic Sans MS">&CONTROL<br> calculation = 'vc-relax',<br> prefix = 'graphene',<br> restart_mode='from_scratch'<br> tstress=.true.,<br> tprnfor=.true.,<br>
nstep=45,<br> etot_conv_thr = 1.0E-4 ,<br> forc_conv_thr = 1.0D-3 ,<br> max_seconds = 36000 ,<br> dt = 100,<br> /<br>&SYSTEM<br> ibrav = 4,<br> celldm(1)= 4.64833<br> celldm(3)=5.447621<br>
nat = 2, <br> ntyp = 1, <br> ecutwfc = 18.0,<br> nbnd =8, <br> occupations='smearing'<br> smearing = 'mv'<br> degauss = 0.005<br> /<br>
&ELECTRONS<br> conv_thr = 1.0d-7<br> electron_maxstep = 70<br> diagonalization='cg'<br> /<br>&IONS<br> ion_dynamics='damp'<br>/<br>&CELL<br> cell_dynamics = 'damp-w' ,<br>
press=0.00 ,<br> wmass=0.0015 ,<br>/<br> <br>ATOMIC_SPECIES<br> C 12.01100 C.pz-vbc.UPF<br>ATOMIC_POSITIONS crystal <br> C 0.00000000 0.00000000 0.50000000<br> C 0.33333333 0.66666666 0.50000000<br>
K_POINTS {automatic}<br> 6 6 6 0 0 0<br></font></div>
<div><font color="#330099" face="Comic Sans MS">Inthis cause: </font></div>
<div><font color="#330099" face="Comic Sans MS"> </font></div>
<div><font color="#330099" face="Comic Sans MS">from electrons : error # 1<br> charge is wrong<br></font></div>
<div><font color="#330099"><font size="2"><font face="comic sans ms,sans-serif">Maybe somebody has already dealed with this problem and can advice the correct options for graphene.</font></font></font></div>
<div><font color="#330099"><font size="2"><font face="comic sans ms,sans-serif">Any suggestion will be appreciated.</font></font></font></div>
<div><br clear="all">-- <br>Best wishes,<br>Olga Sedelnikova<br>Nikolaev Institute of Inorganic Chemistry of SB RAS<br></div>
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