[Pw_forum] Problem with relaxing large system

[Nkosinathi Malaza]

Hi Pascal and  Giovanni,

Thank you so much for the assistance, and the contributions. I will
implement the contributions and let you know how it goes. Again, THANK YOU.

Kind regards


On Fri, Jul 17, 2015 at 10:29 AM, Pascal Boulet <pascal.boulet at univ-amu.fr>
wrote:

> Dear Nkosinathi,
>
> Strictly speaking, your calculation does not crash: it ends up after the
> maximum number of SCF steps is reached. I had a look at the structure and I
> have a few remarks.
>
> 1. Is it normal that the Al-Al distances are 2.8 angstroms long? It seems
> a bit of a large distance to me, but I may be wrong.
> 2. For ultrasoft pseudopotential I would suggest to use 10*ecutwfc for the
> charge density cutoff (see ecutrho).
> 3. It is possible that your system is metallic. Do you use electron
> smearing in your calculation? If not I would try it (see smearing=‘cold'
> and degauss=0.02).
> 4. It is very unlikely that the water molecules are aligned the way they
> are in the input. They should form hydrogen bonds together and interactions
> with the solid. This may also explain why the density is hard to converge:
> the input coordinates are probably very far from the " solution ". If you
> can " improve "  the starting structure it would facilitate the converge.
>
> Hope this help a bit,
> Best regards
> Pascal
>
> Le 17 juil. 2015 à 09:17, Nkosinathi Malaza <nuttymalaza at gmail.com> a
> écrit :
>
> Dear All,
>
> I need assistance with relaxing the system of Al and H2O, the system has
> 123 atoms with ESM=bc3. The input file runs until it crashes, what can be
> the problem?
>
> I have attached the output file.
>
> Kind regards
>
> N. Malaza
> Wits University
> Johannesburg
> South Africa
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> --
> Pascal Boulet *- MCF HDR, Resp. L1 MPCI - DEPARTEMENT CHIMIE*
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