[Pw_forum] polarization:5cells of pbtio3

[stefano de gironcoli]

the coordinates and the lattice vectors are given in unit of alat so you 
need
to add 1.08277316 x 1,2,3,4
where did you get 1.08 from?

In any case you need to run an scf calculation first.

stefano

On 05/09/2015 01:39, Jaret Qi wrote:
> Hello all,
> I'm calculating the polarization of 5 cells of PbTiO3, I have set up 
> the one unit cell correctly and got all of the properties in a good 
> agreement as in literature. But when I tried to calculate the 
> polarization of the 5 cells, I got this error when I run the nscf:
> error: too many bands are not converged,
> The way I constructed the 5 cells is by adding c/a for the 
> z-components of the 2nd cell, 2c/a for the z-components of the 3rd 
> cell, 3c/z for the z-components of the 4th cell, 4c/a for the 
> z-components of the 5th cell.
> see this:
> *1cell :*
> *
> *
> ATOMIC_POSITIONS
> Pb       0.000000000   0.000000000  -0.011923470
> Ti       0.498189800   0.498189800   0.542939650
> O        0.498189800   0.498189800   0.085663538
> O        0.498189800   0.000000000   0.642799807
> O        0.000000000   0.498189800   0.642799807
>
> CELL_PARAMETERS (alat)
>    0.996379599   0.000000000   0.000000000
>    0.000000000   0.996379599   0.000000000
>    0.000000000   0.000000000   1.082777316
>
> *5cells:*
>
> ATOMIC_POSITIONS
> Pb      0.0000000       0.0000000      -0.01192347
> Ti      0.4981898       0.4981898       0.54293965
> O       0.4981898       0.4981898       0.085663538
> O       0.4981898       0.0000000       0.642799807
> O       0.0000000       0.4981898       0.642799807
> Pb      0.0000000       0.0000000       1.06807653
> Ti      0.4981898       0.4981898       1.62293965
> O       0.4981898       0.4981898       1.165663538
> O       0.4981898       0.0000000       1.722799807
> O       0.0000000       0.4981898       1.722799807
> Pb      0.0000000       0.0000000       2.14807653
> Ti      0.4981898       0.4981898       2.70293965
> O       0.4981898       0.4981898       2.245663538
> O       0.4981898       0.0000000       2.802799807
> O       0.0000000       0.4981898       2.802799807
> Pb      0.0000000       0.0000000       3.22807653
> Ti      0.4981898       0.4981898       3.78293965
> O       0.4981898       0.4981898       3.325663538
> O       0.4981898       0.0000000       3.882799807
> O       0.0000000       0.4981898       3.882799807
> Pb      0.0000000       0.0000000       4.30807653
> Ti      0.4981898       0.4981898       4.86293965
> O       0.4981898       0.4981898       4.405663538
> O       0.4981898       0.0000000       4.962799807
> O       0.0000000       0.4981898       4.962799807
> CELL_PARAMETERS (alat)
>    0.996379599   0.000000000   0.000000000
>    0.000000000   0.996379599   0.000000000
>    0.000000000   0.000000000   5.413886650
>
> Is there any problems with the construction of the supercell?
>
>
>
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