[Wien] re-useing previous charge density gives strange total energy

[Hu, Qing Miao]

Dear WIEN2K users,

In my previous calculations using Procedure 2, for the first Rmt*Kmax, I
used the switch '-in1new 3', and for the subsequent Rmt*Kmax, I did not use
the switch but used the *.in1 file with new energy parameters, El,
generated in the calculation for the first Rmt*Kmax.
Just a monment ago, I checked Prodedure 2 again, and used the default energy
parameters for all the SCF calculation. Now, the results is OK.
Does the energy parameters have so significant effect on the total energy?
In fact, the new energy parameters are not so different from the default
ones:
Default                        new
globle    0.3                0.12
0           0.3                0.035
1           0.3                0.175
1       -5.36              -4.173
2           0.3               0.229
I'm totally confused by this problem.


Sincerely yours
Qing Miao Hu

"Hu, Qing Miao" wrote:

> Dear WIEN2K users,
>
> I tested the Rmt*Kmax values for the case of Cu by using different
> procedures. But the total energies given by these prodedures differed
> significantly from each other. Examples are given as the following:
>
>             Procedure 1: Initialize the calculation for each Rmt*Kmax,
> i.e., use the charge density genearated by 'x dstart' for each Rmt*Kmax.
> This procedure gave a total energy of -3310.010662 Ry for Rmt*Kmax=6,
> -3310.061286 Ry for Rmt*Kmax=8, and -3310.064521 Ry for Rmt*Kmax=10;
>
>             Procedure 2: As suggested in the WIEN2K mannual, save the
> results of the calculation for small Rmt*Kmax by using the SAVE command,
> change the Rmt*Kmax to larger one, and then re-calculating. This
> procedure gave a total  energy of -3310.057559 Ry for Rmt*Kmax=8 and
> -3310.051423 for Rmt*Kmax=10, which are obviously unreasonable.
>
>             Procedure 3: make a new directory for larger Rmt*Kmax, only
> copy the nessesary input files (*.in0, *.in1, *.in2, *.inm, *.inc,
> *.struct, *.klist) and the converged charge density for small Rmt*Kmax
> to this directory, change the Rmt*Kmax to larger one. This prodedure
> gave results colse to Prodedure 2.
>
> For all the SCF calculation in the three procedures, the charge density
> converged to 0.0001.
>
> I hope that the problem was resulted from some stupid things I did in
> the calculation, and I will be very grateful if someone could help me to
> find which stupid things I did. Otherwise, it may implicate that the SCF
> calculation is dependent on the initial charge density, which is
> dangerous becuase there maybe losts of WIEN2K users use Procedure 2 or 3
> in order to save computation time.
>
> By the way, I also tested the K mesh by using both Procedure 1 and 2,
> and both gave reasonable results.
>
> Sincerely yours,
> Qing Miao Hu
>
> --
> ---------------------------------------------------
> Dr. Qing Miao Hu
> Fritz-Haber-Institut der Max-Planck-Gesellschaft
> Faradayweg 4-6, D-14195 Berlin-Dahlem, Germany
> Tel: +49 30 8413 4815
> Fax: +49 30 8413 4701
> E-mail: qmhu at FHI-Berlin.MPG.de
> ---------------------------------------------------
>
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> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
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--
---------------------------------------------------
Dr. Qing Miao Hu
Fritz-Haber-Institut der Max-Planck-Gesellschaft
Faradayweg 4-6, D-14195 Berlin-Dahlem, Germany
Tel: +49 30 8413 4815
Fax: +49 30 8413 4701
E-mail: qmhu at FHI-Berlin.MPG.de
---------------------------------------------------