[Pw_forum] SCF calculation don' converge for surface slab

[patriot pershing]

Dear all
i have modified the mixing mode and smearging parameters and the total
energy converge but it take many iteration (14-20 iteration by relax step)

2012/11/12 Lorenzo Paulatto <lorenzo.paulatto at impmc.upmc.fr>

> On 12 November 2012 09:35, patriot pershing <science35 at gmail.com> wrote:
>
>> i talk on energy convergence of the system
>>
>
>
> Surface slabs can be a bit tricky to converge, adding more vacuum normally
> makes it harder.
>
> Your smearing is very small, it may cause states to jump in and out of the
> Fermi (smeared) surface, making convergence unstable. You coudl also try to
> set mixing_mode="local-TF" in &electrons, it helps sometimes.
>
> bests
>
>
>
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> phone: +33 (0)1 44275 084 / skype: paulatz
> www:   http://www-int.impmc.upmc.fr/~paulatto/
> mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
>
>
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