IBI for crystalline phase

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Souvik Chakraborty

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Dec 2, 2019, 4:36:35 AM12/2/19
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Dear Christoph,

I am trying to implement IBI for a crystalline phase coarse-grained from an equillibrated united-atom model. So, the target rdf has a long-range order (attached).

Before doing IBI step, I am trying to simulate the system with the tabulated potentials generated from target distributions. By doing so, I could see the crystal phase is completely destroyed (initial and final snaps are attached).


My query to you:

1. Do the underlying physics of IBI hold for crystalline phase? Or it is only applicable to amorphous liquids?

2. Is there any alternative way/structure-based method to coarse-grain crystalline phase?

Please shed light.

Thanks in advance!

Kind Regards,
Souvik


PS.
I also tried IBI step, but it shows errors due to high force generated between the atoms.
rdf-target-cryst-phase.png
initial-structure.png
final-15ps.png

Christoph Junghans

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Dec 2, 2019, 6:50:45 PM12/2/19
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On Mon, Dec 2, 2019 at 2:36 AM Souvik Chakraborty <souv...@gmail.com> wrote:
>
> Dear Christoph,
>
> I am trying to implement IBI for a crystalline phase coarse-grained from an equillibrated united-atom model. So, the target rdf has a long-range order (attached).
>
> Before doing IBI step, I am trying to simulate the system with the tabulated potentials generated from target distributions. By doing so, I could see the crystal phase is completely destroyed (initial and final snaps are attached).
>
>
> My query to you:
>
> 1. Do the underlying physics of IBI hold for crystalline phase? Or it is only applicable to amorphous liquids?
IBI works best for liquids, but sometimes people get lucky for
crystalline phases, too. It is really system-specific.

>
> 2. Is there any alternative way/structure-based method to coarse-grain crystalline phase?
You could try IMC, RE or the optimizer strategy.
Alternatively, you might want to start IBI with an initial guess for
the potential, which support the crystalline phase, i.e having local
minima at the crystal equilibrium distances.

Christoph
>
> Please shed light.
>
> Thanks in advance!
>
> Kind Regards,
> Souvik
>
>
> PS.
> I also tried IBI step, but it shows errors due to high force generated between the atoms.
>
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--
Christoph Junghans
Web: http://www.compphys.de

Souvik Chakraborty

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Dec 4, 2019, 5:26:52 AM12/4/19
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Thanks a lot, Christoph.

-Souvik
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