Re: [Pw_forum] Finding the most stable structure

[庞瑞(PANG Rui)]

Dear reza
I think the proper way of doing this job is by some optimization algrithoms 
such as genetic algrithom and particle swarm algrithom. You can write a small 
srcript to implement these algrithoms and call pw.x to calculate the energy. As 
alternation, there are some open source software interfaced with pw.x can do 
this job such as CALYPSO. If the structure is not the major property you 
concern, you can use a MD process and reduce the temperature step by step.
Good luck
PangRui




--


庞瑞(PANG Rui)



South University of Science and Technology of China/Department of Physics

No.1088,Xueyuan Road, Shenzhen,Guangdong







 
 
 
-- Original --
From:  "reza vatan";
Date:  Mon, Sep 28, 2015 03:54 AM
To:  "PWSCF Forum"; 

Subject:  [Pw_forum] Finding the most stable structure

 
Dear all,


I have a supercell containing 64 Si atoms with amorphous structure and I want 
to add one Hydrogen atom to one of Si atoms with the condition that the most 
stable possible structure comes out. I randomly add the Hydrogen to one of Si 
atoms and then I run "relax" calculations, but I get different final energy 
when I repeat my random process for adding the Hydrogen. Should I try "md" 
calculations to get the same structure with the most stability out of my 
different initial structures? If yes under which conditions (options)?


Any suggestion would be highly appreciated.


Best,

Reza 

--

Reza Vatan Meidanshahi

Electrical Engineering Department

Arizona State University___
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Re: [Pw_forum] Finding the most stable structure

[Mostafa Youssef]

Dear Reza,

Exploring the potential energy surface of glassy systems is not a trivial 
problem not to mention impurities in glassy systems. Depending on how deep you 
want to explore this,  you may want to explore PLUMED package which is 
compatible with PWscf.

http://www.plumed-code.org/

For something quick, I would run an MD at very high temperature , take 100 
snapshots from the run , and relax them at zero temperature.

Regards,
Mostafa
MIT
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[Pw_forum] Finding the most stable structure

[reza vatan]

Dear all,

I have a supercell containing 64 Si atoms with amorphous structure and I
want to add one Hydrogen atom to one of Si atoms with the condition that
the most stable possible structure comes out. I randomly add the Hydrogen
to one of Si atoms and then I run "relax" calculations, but I get different
final energy when I repeat my random process for adding the Hydrogen.
Should I try "md" calculations to get the same structure with the most
stability out of my different initial structures? If yes under which
conditions (options)?

Any suggestion would be highly appreciated.

Best,
Reza

--
Reza Vatan Meidanshahi
Electrical Engineering Department
Arizona State University
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