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[Suleyman Çabuk <scabuk@cu.edu.tr>]

Dear users;

  I tried to optimize the atomic positions of BaTiO3 in tetragonal  
phase.         My results: Ti position: 0.500000639 (0.000000639)
                                   O1 position: 8.6829899663E-08

 Exp. results: Ti: 0.0224
              O1: -0.0244 (Ref. J. Phys. Chem. 97, p.2368)

 Cal. results:  Ti: 0.0136
              O1: -0.0273 (Ref. Ph.D Thesis, Viethen Marek, 2005)

 Why are my results (Ti and O1 position) very small? What is it  
wrong? I am really confused about that. Could anybady give me some  
suggestions?

 Thanks.

 My input data:
 ndtset   2
 # Set 1 : Internal coordinate optimization

  ionmov1   2
   ntime1   1000
  tolmxf1   1.0e-5

  natfix1   1

  iatfix1   1
  natfixx1   4
  atfixx1   2 3 4 5
  natfixy1   4
  atfixy1   2 3 4 5


 # Set 2 : Lattice parameter relaxation (including re-optimization of
 #         internal coordinates)

 dilatmx2   1.05
 getxred2   -1
  getwfk2   -1
  ionmov2   2
   ntime2   1000
 optcell2   2
  tolmxf2   1.0e-5
 strfact2   100

  natfix2   1
  iatfix2   1
  natfixx2   4
  atfixx2   2 3 4 5
  natfixy2   4
  atfixy2   2 3 4 5

 #Starting approximation for the unit cell
  acell   2*7.5  7.8           #

  rprim  1.0  0.0  0.0
         0.0  1.0  0.0
         0.0  0.0  1.0

 #Definition of the atom types and atoms
   natom       5
   ntypat      3
   znucl       56 22 8
   typat       1 2 3*3

 xred
    0.0 0.0 0.0
    0.5 0.5 0.53
    0.5 0.5  -0.03
    0.5 0.0   0.47
    0.0 0.5   0.47

 #Gives the number of bands, explicitely (do not take the default)
  nband   12

 #Definition of the plane wave basis set
   ecut   38
 ecutsm   0.5

 #Definition of the k-point grid
 kptopt   1
  ngkpt   6 6 6
 nshiftk   1
 shiftk   0.5 0.5 0.5

 #Definition of the self-consistency procedure

   iscf   5
  nstep   1000
 tolvrs   1.0d-12

 ----------------------------------------------------------------------------------
 my output:

 DATASET    1 : space group P4 m m (# 99); Bravais tP (primitive  tetrag.)
 ======================================================================
 Values of the parameters that define the memory need for DATASET  1.
   intxc =         0  ionmov =         2    iscf =         5     ixc  =         7
  lmnmax =         4   lnmax =         4   mband =        12  mffmem   =         1
 P  mgfft =        45   mkmem =        18 mpssoang=         4     mpw   =      4927
  mqgrid =      1201   natom =         5    nfft =     91125    nkpt   =        18
  nloalg =         4  nspden =         1 nspinor =         1  nsppol   =         1
    nsym =         8  n1xccc =      2501  ntypat =         3  occopt  

======================================================================
 P This job should need less than                      39.260 Mbytes  
of memory.
  Rough estimation (10% accuracy) of disk space for files :
  WF disk file :     16.241 Mbytes ; DEN or POT disk file :       
0.697 Mbytes.
 
======================================================================

 DATASET    2 : space group P4 m m (# 99); Bravais tP (primitive   tetrag.)
 ======================================================================
 Values of the parameters that define the memory need for DATASET  2.
   intxc =         0  ionmov =         2    iscf =         5     ixc   =         7
  lmnmax =         4   lnmax =         4   mband =        12  mffmem =         1
 P  mgfft =        48   mkmem =        18 mpssoang=         4     mpw  =      5714
  mqgrid =      1201   natom =         5    nfft =     97200    nkpt   =        18
  nloalg =         4  nspden =         1 nspinor =         1  nsppol   =         1
    nsym =         8  n1xccc =      2501  ntypat =         3  occopt =         1
 ======================================================================
 P This job should need less than                      43.632 Mbytes  
of memory.
  Rough estimation (10% accuracy) of disk space for files :
  WF disk file :     18.835 Mbytes ; DEN or POT disk file :       
0.744 Mbytes.
 ======================================================================
 == END DATASET(S)  
==============================================================
 ======================================================================

 -outvars: echo values of variables after computation  --------
     acell1   7.5000000000E+00  7.5000000000E+00  7.8000000000E+00 Bohr
     acell2   7.4924150874E+00  7.4924157563E+00  7.4924318056E+00 Bohr
       amu    1.37327000E+02  4.78800000E+01  1.59994000E+01
   dilatmx1   1.00000000E+00
   dilatmx2   1.05000000E+00
      ecut    3.80000000E+01 Hartree
    ecutsm    5.00000000E-01 Hartree
    etotal1  -5.3244809276E+01
    etotal2  -5.3247202682E+01

      xred1   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
              5.0000000000E-01  5.0000000000E-01  5.2149584551E-01
              5.0000000000E-01  5.0000000000E-01 -2.6942770167E-02
              5.0000000000E-01  0.0000000000E+00  4.9105509172E-01
              0.0000000000E+00  5.0000000000E-01  4.9105509172E-01
      xred2   0.0000000000E+00  0.0000000000E+00  0.0000000000E+00
              5.0000000000E-01  5.0000000000E-01  5.0000006390E-01   #Ti
              5.0000000000E-01  5.0000000000E-01  8.6829899663E-08   #O1
              5.0000000000E-01  0.0000000000E+00  4.9999998386E-01
              0.0000000000E+00  5.0000000000E-01  4.9999998386E-01