[Pw_forum] about the from scale_h : error

[Wei Zhou]

first thank your for your help......

the relaxed structure  from vasp at 500kba is
Ba
   3.12000000000000
     1.0202516248839648    0.0000000000000000    0.0000000000000000
    -0.5101258124419824    0.8835632605198342    0.0000000000000000
     0.0000000000000000    0.0000000000000000    1.6154107754936728
   2
Direct
  0.3333333300000021  0.6666659999999993  0.2500000000000000
  0.6666666599999971  0.3333330000000032  0.7500000000000000
  external pressure =        1.67 kB  Pullay stress =      500.00 kB

 pwscf input is celldm(1)=6.015350,celldm(3)=1.58,
Bohr=5.2917706   angstrom
I have changed the input file like this after accepting your suggestions
&control
    calculation='vc-relax',
    restart_mode='from_scratch',
    dt=80,
    prefix='ba',
    pseudo_dir = '/home/solid/Work/PW/pseudo/',
    outdir='/home/solid/Work/PW/temp/'
    tstress=.t.,
    tprnfor=.t.
    nstep= 100
/
 &system
    ibrav= 4,
    celldm(1)=6.0,
    celldm(3)=1.58,
    nat= 2,
    ntyp=1,
    nbnd=30
    ecutwfc=30.0,ecutrho = 300
    nosym = .f. ,
    occupations = 'smearing' ,
    degauss = 0.014D0 ,
    smearing = 'methfessel-paxton' ,
/
 &electrons
    mixing_beta = 0.7
    conv_thr =  1.0d-8
/
 &IONS
    ion_dynamics = 'bfgs' ,
/
 &CELL
    cell_dynamics = 'bfgs' ,
    press_conv_thr = 0.1 ,
    press = 500
/
ATOMIC_SPECIES
Ba  137.327 Ba.pbe-nsp-van.UPF
ATOMIC_POSITIONS {crystal}
Ba 0.3333333333333286 0.6666666666666714 0.2500000000000000
Ba 0.6666666666666714 0.3333333333333286 0.7500000000000000
K_POINTS {automatic}
14 14 8  0 0 0
then the error still is
task #         0
     from scale_h : error #         1
     Not enough space allocated for radial FFT: try restarting with a larger
cell_factor.
if I add the cell_factor =3.0 to the &CELL, then the error became

 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     task #         2
     from electrons : error #         1
     charge is wrong
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

the relaxed pressure changes unexpectly as following
  grep kba *
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=  356.22
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=  420.98
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=  105.79
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=-1505.88
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P= 9429.67
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=-1476.75
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=-1702.03
ba.optim.out_500:          total   stress  (Ry/bohr**3)
(kbar)     P=-2923.68

2010/3/3 Lorenzo Paulatto <paulatto at sissa.it>

> On Wed, 03 Mar 2010 12:30:32 +0100, Wei Zhou <zdw2000 at gmail.com> wrote:
> >> the initial structure is get from the VASP soft,and is consist with the
> >> experiment at 500kba,
>
> Dear Wei,
> I think you may have done a unit of measure mistake while converting the
> system parameters from VASP to QE. In order to get the huge pressure you
> are requiring the cell parameter has to shrink by a factor ~ 0.57 (i.e not
> too far away from the bohr/Angstrom conversion). Furthermore, you smearing
> degauss is probably too high (remember it is expressed in Rydberg) and you
> cutoff energy is probably unnecessarily high (the pseudopotential you are
> using is well converged at much lower ecutwfc and ecutrho).
>
> > I wonder if the two Ba pseudo potential of pwscf web cannot  work at
> > high pressre..........
>
> It is possible: when the atoms get very close to each other you need
> harder pseudopotentials; however that's not the cause of your problem, I
> would bet on the smearing instead.
>
> regards
>
> --
> Lorenzo Paulatto
>
> *** Note: my affiliation has changed! please send future
> correspondence to: <Lorenzo.Paulatto at impmc.upmc.fr> ***
>
> post-doc @ IMPMC/UPMC - Université Paris 6
> phone: +33 (0)1 44 27 74 89
> www:   http://www-int.impmc.upmc.fr/~paulatto/
>
> previously:
> phd student @ SISSA  &  DEMOCRITOS (Trieste)
> phone: +39 040 3787 511
> www:   http://people.sissa.it/~paulatto/
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-- 
ZhouDawei
JiLin Universiyt ,ChangChun ,China
zdw2000 at gmail.com
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