[Wien] Oscillating convergence

[Tran, Fabien]

Do first a GGA PBE calculation, save it, and then the HSE calculation with alpha=0.05 and with the default case.inm (MSR1).

________________________________________
From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> on behalf of shamik chakrabarti <shamik15041981 at gmail.com>
Sent: Wednesday, January 12, 2022 9:19 AM
To: A Mailing list for WIEN2k users
Subject: Re: [Wien] Oscillating convergence

Dear Prof. Blaha,

                       By  grid to 0.01, I mean the mixing parameter in case.inm ( I change 0.2 to 0.01). For a trial can I check by reducing the alpha from 0.25 to 0.05 in case.inhf now? Or I need to start with 0.05 as alpha from the scratch?

Looking forward to your reply.

with regards,



On Wed, 12 Jan 2022 at 13:38, Peter Blaha <pblaha at theochem.tuwien.ac.at<mailto:pblaha at theochem.tuwien.ac.at>> wrote:
I'm not too surprised. In HSE there is not only a dependency on the
density (which is "mixed") but also on the wave functions. This HF
potential due to them is "mixed" with 100 %.

Maybe it helps when using a small alpha at the beginning (0.05 instead
of 0.25) for the amount of HF (case.inhf), later on increase it when
reasonably converged.

PS: I would probably not play with PRATT (except you can clearly
decrease :DIS significantly without oszillations) and I don't know what
you mean with:  "grid to 0.01" ???

Am 12.01.2022 um 08:51 schrieb shamik chakrabarti:
> Dear Wien2k users,
>
>                        I have started a simulation of ABCO4 oxide
> material with 64 atomic unit cell using HSE06. However, the energy &
> charge convergence is oscillating between 0.08-0.008 and 0.5 - 0.2 for
> around 100 cycles. The same structure was converged using GGA+U. I have
> used 1 k-point & also change the grid to 0.01 & used PRATT for several
> cycles now. What could be the remedy?
>
> (1) Is it that we need to use more than 1 k-point for convergence
> (2) There is something wrong with the structure (However the same
> structure is converged with GGA+U)
>
> Looking forward to hearing from you.
>
> with regards,
>
> --
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
>
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--
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--
Dr. Shamik Chakrabarti
Research Fellow
Department of Physics
Indian Institute of Technology Patna
Bihta-801103
Patna
Bihar, India