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[NISHIMATSU Takeshi <t-nissie@imr.tohoku.ac.jp>]

Dear Okuno-san,

Which pseudopotentials do you use?
With Teter's extended norm-conserving pseudopotentials,
I could reach convergence.

-- Takeshi NISHIMATSU

Can I introduce our article using ABINIT?
 Japanese Journal of Applied Physics
 Vol. 43, No. 9B, 2004, pp. 6785-6792
 Title: Ab initio Determination of Total-Energy Surfaces
for Distortions of Ferroelectric Perovskite Oxides
 Author: Takatoshi HASHIMOTO, Takeshi NISHIMATSU, Hiroshi MIZUSEKI,
Yoshiyuki KAWAZOE, Atsushi SASAKI and Yoshiaki IKEDA
 Abstract: We established a new ab initio structure optimization
technique of determining the valley line on a total-energy surface
accurately for the zone-center distortions of ferroelectric perovskite
oxides, and applied this technique to the analysis of barium titanate
(BaTiO3), lead titanate (PbTiO3), and lead zirconate (PbZrO3).
The proposed technique is an improvement over King-Smith and Vanderbilt's
scheme [Phys. Rev. B 49 (1994) 5828] of evaluating total energy as
a function of the amplitude of atomic displacements. The results of
numerical calculations show that total energy can be expressed as a
fourthorder function of the amplitude of atomic displacements in BaTiO3
but not in PbTiO3 and PbZrO3. These results will provide some hints about
the reason Pb(ZrxTi1-x)O3(PZT) has a large piezoelectric response.
These results are due to the fact that our structure optimization
technique automatically takes account of the higher-order coupling
between atomic displacements and strains, and not only the atomic
displacements of the Gamma_15 soft mode but also that of the hard modes.

Here's mine:
optcell 2
ionmov 2
ntime 20

prtwf 0

ecut 36.0
ecutsm 5.0
dilatmx 1.1
ixc 3

acell    7.3003874768E+00  7.3003874766E+00  7.5076871324E+00

rprim  1 0 0
       0 1 0
       0 0 1

#Definition of the atom types
ntypat 3
znucl 82 22 8

#Definition of the atoms
natom 5
typat 1*1 1*2 3*3
xred
  0.0 0.0  0.058837116221
  0.5 0.5  0.52782095761
  0.0 0.5  0.46779025357
  0.5 0.0  0.46779025357
  0.5 0.5 -0.016446573428

#Definition of the k-point grid
kptopt 1
ngkpt  8 8 8
nshiftk 1
shiftk 0.5 0.5 0.5

#Definition of the SCF procedure
nstep 35
toldff 5.0d-7     # Use force!
diemac 12.0


% grep -n -e 'total e' perovskite.out /dev/null
perovskite.out:322: At the end of Broyden step  0, total energy= 
-1.65947093938423E+02 Ha.
perovskite.out:377: At the end of Broyden step  1, total energy= 
-1.65947095192551E+02 Ha.
perovskite.out:432: At the end of Broyden step  2, total energy= 
-1.65947095392775E+02 Ha.
perovskite.out:479: At the end of Broyden step  3, total energy= 
-1.65947095412853E+02 Ha.
perovskite.out:527: At the end of Broyden step  4, total energy= 
-1.65947095459121E+02 Ha.

% grep -n -e 'acell' perovskite.out /dev/null
perovskite.out:41:     acell    7.3003874768E+00  7.3003874766E+00  
7.5076871324E+00 Bohr
perovskite.out:302:  acell=  7.3003874768E+00  7.3003874766E+00  
7.5076871324E+00
perovskite.out:357:  acell=  7.3016054025E+00  7.3016054022E+00  
7.5097085106E+00
perovskite.out:412:  acell=  7.3021657874E+00  7.3021657868E+00  
7.5110127492E+00
perovskite.out:459:  acell=  7.3021198763E+00  7.3021198753E+00  
7.5112936577E+00
perovskite.out:507:  acell=  7.3016759257E+00  7.3016759209E+00  
7.5125046292E+00
perovskite.out:938:     acell    7.3016759257E+00  7.3016759209E+00  
7.5125046292E+00 Bohr