<div>first thank your for your help...... </div>
<div> </div>
<div>the relaxed structure from vasp at 500kba is </div>
<div>Ba <br> 3.12000000000000 <br> 1.0202516248839648 0.0000000000000000 0.0000000000000000<br> -0.5101258124419824 0.8835632605198342 0.0000000000000000<br> 0.0000000000000000 0.0000000000000000 1.6154107754936728<br>
2<br>Direct<br> 0.3333333300000021 0.6666659999999993 0.2500000000000000<br> 0.6666666599999971 0.3333330000000032 0.7500000000000000</div>
<div> external pressure = 1.67 kB Pullay stress = 500.00 kB<br><br> pwscf input is celldm(1)=6.015350,celldm(3)=1.58, <br><font color="#cc0033">Bohr</font>=5.2917706 angstrom</div>
<div>I have changed the input file like this after accepting your suggestions</div>
<div>&control<br> calculation='vc-relax',<br> restart_mode='from_scratch',<br> dt=80,<br> prefix='ba',<br> pseudo_dir = '/home/solid/Work/PW/pseudo/',<br> outdir='/home/solid/Work/PW/temp/'<br>
tstress=.t.,<br> tprnfor=.t.<br> nstep= 100<br>/<br> &system<br> ibrav= 4,<br> celldm(1)=6.0,<br> celldm(3)=1.58,<br> nat= 2,<br> ntyp=1,<br> nbnd=30<br> ecutwfc=30.0,ecutrho = 300<br> nosym = .f. ,<br>
occupations = 'smearing' ,<br> degauss = 0.014D0 ,<br> smearing = 'methfessel-paxton' ,<br>/<br> &electrons<br> mixing_beta = 0.7<br> conv_thr = 1.0d-8<br>/<br> &IONS<br> ion_dynamics = 'bfgs' ,<br>
/<br> &CELL<br> cell_dynamics = 'bfgs' ,<br> press_conv_thr = 0.1 ,<br> press = 500<br>/<br>ATOMIC_SPECIES<br>Ba 137.327 Ba.pbe-nsp-van.UPF <br>ATOMIC_POSITIONS {crystal}<br>Ba 0.3333333333333286 0.6666666666666714 0.2500000000000000<br>
Ba 0.6666666666666714 0.3333333333333286 0.7500000000000000<br>K_POINTS {automatic}<br>14 14 8 0 0 0<br>then the error still is </div>
<div>task # 0<br> from scale_h : error # 1<br> Not enough space allocated for radial FFT: try restarting with a larger cell_factor.<br>if I add the cell_factor =3.0 to the &CELL, then the error became</div>
<div> </div>
<div> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br> task # 2<br> from electrons : error # 1<br> charge is wrong<br> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%<br>
<br>the relaxed pressure changes unexpectly as following </div>
<div> grep kba *<br>ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P= 356.22<br>ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P= 420.98<br>ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P= 105.79<br>
ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P=-1505.88<br>ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P= 9429.67<br>ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P=-1476.75<br>
ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P=-1702.03<br>ba.optim.out_500: total stress (Ry/bohr**3) (kbar) P=-2923.68<br><br></div>
<div class="gmail_quote">2010/3/3 Lorenzo Paulatto <span dir="ltr"><<a href="mailto:paulatto@sissa.it">paulatto@sissa.it</a>></span><br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div class="im">On Wed, 03 Mar 2010 12:30:32 +0100, Wei Zhou <<a href="mailto:zdw2000@gmail.com">zdw2000@gmail.com</a>> wrote:<br>>> the initial structure is get from the VASP soft,and is consist with the<br>
>> experiment at 500kba,<br><br></div>Dear Wei,<br>I think you may have done a unit of measure mistake while converting the<br>system parameters from VASP to QE. In order to get the huge pressure you<br>are requiring the cell parameter has to shrink by a factor ~ 0.57 (i.e not<br>
too far away from the bohr/Angstrom conversion). Furthermore, you smearing<br>degauss is probably too high (remember it is expressed in Rydberg) and you<br>cutoff energy is probably unnecessarily high (the pseudopotential you are<br>
using is well converged at much lower ecutwfc and ecutrho).<br>
<div class="im"><br>> I wonder if the two Ba pseudo potential of pwscf web cannot work at<br>> high pressre..........<br><br></div>It is possible: when the atoms get very close to each other you need<br>harder pseudopotentials; however that's not the cause of your problem, I<br>
would bet on the smearing instead.<br><br>regards<br><br>--<br>Lorenzo Paulatto<br><br>*** Note: my affiliation has changed! please send future<br>correspondence to: <<a href="mailto:Lorenzo.Paulatto@impmc.upmc.fr">Lorenzo.Paulatto@impmc.upmc.fr</a>> ***<br>
<br>post-doc @ IMPMC/UPMC - Université Paris 6<br>phone: +33 (0)1 44 27 74 89<br>www: <a href="http://www-int.impmc.upmc.fr/~paulatto/" target="_blank">http://www-int.impmc.upmc.fr/~paulatto/</a><br><br>previously:<br>phd student @ SISSA & DEMOCRITOS (Trieste)<br>
phone: +39 040 3787 511<br>www: <a href="http://people.sissa.it/~paulatto/" target="_blank">http://people.sissa.it/~paulatto/</a><br>
<div>
<div></div>
<div class="h5">_______________________________________________<br>Pw_forum mailing list<br><a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br><a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>ZhouDawei<br>JiLin Universiyt ,ChangChun ,China<br><a href="mailto:zdw2000@gmail.com">zdw2000@gmail.com</a><br>