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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Dear Duan

Although i'm not completely sure it will affect a non-SCF calculation,
it may also be useful to increase "nline": For the systems where you
can notice that even though vres2 converges correctly residm does not,
you may get much better convergence of wavefunction with a greater
value for nline (for instance 12). Notice that greater values of nline
increase the time spent in wavefunctions optimisation.

regards

PMA

On 8/15/07, Xavier Gonze <gonze@pcpm.ucl.ac.be> wrote:
> 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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-- 
Pierre-Matthieu Anglade