[CP2K-user] Co(111) Geometry optimization with kpoints

[Manuel Corral]

Dear Fabian,

Thank you very much for the commented file. It works, which it is already a 
huge improvement, though it may take about 75 electronic iterations for 
each ionic step, which may render a MD calculation too expensive. I wonder 
if there is anything that could be done to speed it up.

By the way, why do  you need to rotate the cell for the Wavelet Poisson 
solver ? Based on this rotation, I would have thought of changing the 
Monkhorst Pack set of k-points from 7x7x1 to 7x1x7, which you didn't and, 
when I tried it, it did not work properly:

 *** WARNING in pw/ps_wavelet_methods.F:236 :: Density non-zero on the ***
 *** edges of the unit cell: wrong results in WAVELET solver.

Thanks again.

Regards,
Manuel

Le lundi 18 janvier 2021 à 18:03:26 UTC+1, fa... at gmail.com a écrit :

> Dear Manuel,
>
> I changed a couple of things in the input and it's converging now 
> (attached below). The changes include:
> To use the WAVELET poisson solver I rotated the slab such that B is the 
> surface vector. 
> I also decreased RELAX_MULTIPLICITY because large values hinder scf 
> onvergence. Maybe you need to test various initial guesses (see here: 
> https://manual.cp2k.org/cp2k-8_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/KIND/BS.html) 
> to find the minimal energy configuration.
> I increased the ELECTRONIC_TEMPERATURE in the &SEMEAR section. 300 K 
> corresponds to just 0.02 eV in VASP which is very little.
>
> Cheers,
> Fabian
>
> On Monday, 18 January 2021 at 14:53:36 UTC+1 Manuel Corral wrote:
>
>> Dear Colleagues,
>>
>> I have been trying to run a geometry optimization for with a Co(111) 
>> 4-layer slab model without success. 
>>
>> I set up my initial input file according my previous experience with 
>> another software (VASP) and then changed different calculation settings: 
>> number of additional MOS (10, 30, 100), electronic temperature of the 
>> smearing (300 K, 500 K), decreasing the cell in the vacuum direction, 
>> changing the number of kpoints (gamma point with an increased cell), the 
>> Poisson solver (analytical vs non analytical), the diagonalization 
>> algorithm, settings in the mixing algorithm ... nothing worked. The SCF 
>> cycle never converges.
>>
>> I would very much appreciate if you could give some advice or feedback on 
>> my input files (enclosed).
>>
>> Thank you in advance for your help.
>>
>> Kind regards,
>> Manuel Corral
>>
>>
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