[Wien] Large oscillations in total energy

[Laurence Marks]

I suggest using the "Check" command, which shows more useful information
and post the output. Without that it is hard to guess.

_____
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu

On Dec 7, 2017 4:20 AM, "Pavel Ondračka" <pavel.ondracka at email.cz> wrote:

> Dear Wien2k mailing list,
>
> I'm seeing some strange energy oscillations in one calculation near the
> end when everything seems almost converged.
>
> :ENERGY convergence:  0 0.0001 .0039009700000000
> :ENERGY convergence:  0 0.0001 .0168906450000000
> :ENERGY convergence:  0 0.0001 .0096598000000000
> :ENERGY convergence:  0 0.0001 .0162053350000000
> :ENERGY convergence:  0 0.0001 .0089683200000000
> :ENERGY convergence:  0 0.0001 55.6398533450000000
> :ENERGY convergence:  0 0.0001 27.8210445050000000
> :ENERGY convergence:  0 0.0001 27.8235252600000000
>
> the charge is converged already:
>
> :CHARGE convergence:  1 0.001 -.000920
> :CHARGE convergence:  1 0.001 -.000977
> :CHARGE convergence:  1 0.001 -.000933
> :CHARGE convergence:  1 0.001 -.000972
> :CHARGE convergence:  1 0.001 -.000984
> :CHARGE convergence:  1 0.001 -.000988
> :CHARGE convergence:  1 0.001 -.000997
> :CHARGE convergence:  1 0.001 -.000998
>
> This is quite large calculation of TiSiO amorphous-like cell (96 atoms,
>  struct file attached, compressed in order to pass the moderation
> queue). The numerical parameters are quite standard,
> 2x2x2 shifted k-grid (can also reproduce this with 3x3x3), Rkmax 7.5,
> PBE, rest of stuff at default. I have done a lot of calculation with
> similar cells and such parameters without any problems (albeit mostly
> some time ago with older Wien2k versions)...
>
> I'm trying to calculate the binding energy of the O 1s for the first
> oxygen using the Slaters transition state approach. Surprisingly when I
> use almost touching spheres it converges (O:1.48, Ti: 1.72, Si:1.48),
> however when I reduce them by 3% (as in the attached struct file) this
> problems surfaces. However I need this reduced spheres for comparison
> with another calculation. BTW the spheres around 1.5 for oxygen
> should be reasonable anyway?
>
> No errors or warnings anywhere, except for the expected
> WARN  :        CHARGED CELL with  -0.500
>
> This is with Wien2k 17.1, compiled with MKL 2017.0.098 and ifort.
>
> Any ideas what might be causing this problem?
> Best regards
> Pavel
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