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[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear duan_semi,

Note that vres2 is converged, which is the key. So, your piezoelectric constant

is likely correct.

I would bet that the problem with tolwfr is only due to the

highest state (band) treated , that is likely

degenerate with a state not treated  by ABINIT.

In this case, putting by hand the input variable nband to the exact number of bands requested

to fill the valence bands and leave empty all the conduction bands will do the work.

Xavier

On 15 Aug 2007, at 03:09, duan_semi wrote:

Hello, everyone,

         I want to calculate the piezoelectric constants, but it is difficult to reach convergence according to "tolwfr".

#########################################################

 Perturbation wavevector (in red.coord.)   0.000000  0.000000  0.000000
 Perturbation : displacement of atom   3   along direction   1
 The set of symmetries contains only one element for this perturbation.
 symkpt : not enough symmetry to change the number of k points.

……………………………………………………………………

   iter   2DEtotal(Ha)                        deltaE(Ha) residm    vres2
-ETOT  1   42.724297280364     -5.199E+01 1.269E+00 2.839E+05
 ETOT  2   20.269193338727     -2.246E+01 2.226E-01 1.907E+04
 ETOT  3   18.688028565490     -1.581E+00 3.866E-01 3.284E+04
 ETOT  4   16.763178500864     -1.925E+00 1.115E-01 1.238E+04
 ETOT  5   15.760797588090     -1.002E+00 3.314E-01 4.965E+02
 ETOT  6   15.733566513200     -2.723E-02 8.950E-02 6.369E+01
 ETOT  7   15.731118447863     -2.448E-03 3.227E-01 3.621E+01
 ETOT  8   15.729136359359     -1.982E-03 9.742E-02 1.251E+01
 ETOT  9   15.728553493960     -5.829E-04 3.648E-01 5.929E-01
 ETOT 10   15.728521281135     -3.221E-05 1.115E-01 8.326E-02
 ETOT 11   15.728518381349     -2.900E-06 4.178E-01 3.976E-02
 ETOT 12   15.728516732921     -1.648E-06 1.291E-01 1.635E-02
 ETOT 13   15.728516043809     -6.891E-07 4.808E-01 1.519E-03
 ETOT 14   15.728515935550     -1.083E-07 1.496E-01 1.312E-04
 ETOT 15   15.728515931338     -4.212E-09 5.550E-01 3.826E-05
 ETOT 16   15.728515927783     -3.555E-09 1.385E-01 1.339E-05
 ETOT 17   15.728515926319     -1.465E-09 6.124E-01 1.071E-06
 ETOT 18   15.728515926262     -5.681E-11 4.448E-01 2.380E-07
 ETOT 19   15.728515926254     -7.290E-12 4.891E-01 9.279E-08
 ETOT 20   15.728515926250     -3.979E-12 1.721E-01 2.711E-08
 ETOT 21   15.728515926248     -2.913E-12 1.226E-01 2.120E-09
 ETOT 22   15.728515926246     -1.194E-12 1.708E-01 3.329E-10
 ETOT 23   15.728515926248      1.876E-12 1.177E-01 1.762E-10
 ETOT 24   15.728515926247     -1.137E-12 1.849E-01 5.729E-11
 ETOT 25   15.728515926246     -1.421E-12 1.308E-01 2.876E-12
 ETOT 26   15.728515926247      1.478E-12 2.053E-01 5.853E-13
 ETOT 27   15.728515926246     -1.151E-12 1.466E-01 1.797E-13
 ETOT 28   15.728515926247      1.108E-12 2.301E-01 5.565E-14
 ETOT 29   15.728515926248      4.832E-13 1.646E-01 9.428E-15
 ETOT 30   15.728515926247     -1.705E-13 2.590E-01 9.442E-16
 ETOT 31   15.728515926248      2.132E-13 1.850E-01 3.344E-16
 ETOT 32   15.728515926247     -5.826E-13 2.922E-01 4.058E-17
 ETOT 33   15.728515926246     -6.395E-13 2.081E-01 1.347E-17
 ETOT 34   15.728515926247      4.832E-13 3.302E-01 1.586E-18
 ETOT 35   15.728515926247     -1.705E-13 4.524E-01 6.160E-19
 ETOT 36   15.728515926247      2.558E-13 2.292E-01 1.066E-19
 ETOT 37   15.728515926247      8.527E-14 5.387E-01 1.771E-20
 ETOT 38   15.728515926247     -4.263E-14 4.448E-01 1.838E-21
 ETOT 39   15.728515926247      8.527E-14 1.658E-01 1.467E-21
 ETOT 40   15.728515926247      1.279E-13 4.891E-01 3.895E-22
 ETOT 41   15.728515926247     -2.842E-14 1.721E-01 4.055E-23
 ETOT 42   15.728515926247     -2.842E-14 1.708E-01 4.215E-24
 ETOT 43   15.728515926247     -1.421E-14 1.308E-01 1.926E-24
 ETOT 44   15.728515926247     -1.421E-14 1.849E-01 6.630E-25
 ETOT 45   15.728515926247      0.000E+00 1.466E-01 1.195E-25
-open ddk wf file :znbeoo_DS2_1WF49
-open ddk wf file :znbeoo_DS2_1WF50
-open ddk wf file :znbeoo_DS2_1WF51
######################################################

In the second step to calculate "ddk", the situation is of the same.

 

Thank you very much in advance,

Dewei

 

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