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Re: [lammps-users] How hybrid/overlay works, especifically in case of AIREBO and TERSOFF
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Re: [lammps-users] How hybrid/overlay works, especifically in case of AIREBO and TERSOFF


From: "Nasiri, Samaneh" <samaneh.nasiri@...4839...>
Date: Mon, 11 Sep 2017 16:00:52 +0000

Dear lammps users,

regarding the last question, I have read the hybrid pair_style and there is an explanation as this :

>>>Here is another example, using hybrid/overlay, to use 2 many-body potentials together, in an >>>overlapping manner. Imagine you have CNT (C atoms) on a Si surface. You want to use Tersoff >>>for Si/Si and Si/C interactions, and AIREBO for C/C interactions. Si atoms are type 1; C atoms >>>are type 2. Something like this will work:
>>>pair_style hybrid/overlay tersoff airebo 3.0
>>>pair_coeff * * tersoff SiC.tersoff.custom Si C
>>>pair_coeff * * airebo CH.airebo NULL C

>>>Note that to prevent the Tersoff potential from computing C/C interactions, you would need to >>>modify the SiC.tersoff file to turn off C/C interaction, i.e. by setting the appropriate coefficients

>>>to 0.0.



I read lots of literature and finally I understand that I should put A and B in CCC line to zero? But I am not sure if it is the case. Shoul I change some parameters about three body interactions?


Bests,

Samaneh

--
Samaneh Nasiri, M.Sc.
Doctorate Candidate at Institute for Materials Simulation (WW8)

Department of Materials Science
Friedrich-Alexander-University Erlangen-Nürnberg

Dr.-Mack-Str. 77, 90762 Fürth, Germany
Room: 2.024
phone: +49 911 65078-65065
fax:   +49 911 65078-65066


Dear lammps users

I am working on mechanical properties of platinum-carbon composites using MD method. There is a bond order potential field introduced by Prof. Albe
( DOI: 10.1103/PhysRevB.65.195124 ) which can represent the short ranged  interaction between Pt-Pt , C-C and Pt-C. In my simulation I need to consider the long range interactions between carbon atoms. To do that, I decided to use AIREBO potential for C-C and Tersoff for Pt-Pt and Pt-C by hybrid/overlay method in LAMMPS.

To solve this issue I read the LAMMPS  documentation and  paper about AIREBO potential and Tersoff potential from Prof. Albe paper to understand the meaning of the parameters in both potential file. After lots of confusions, finally I understand that if I put the 'A' and 'B' parameters in potential file to zero for C C C row in tersoff file I can turn off the C-C interaction. 

Do you think the whole approach is correct? I mean the potential field that I chose and the way that I am using them is correct ? I really appreciate if you have any suggestion regarding this issue.

Thanks in advance,

Best regards,

Samaneh

--
Samaneh Nasiri, M.Sc.
Doctorate Candidate at Institute for Materials Simulation (WW8)

Department of Materials Science
Friedrich-Alexander-University Erlangen-Nürnberg

Dr.-Mack-Str. 77, 90762 Fürth, Germany
Room: 2.024
phone: +49 911 65078-65065
fax:   +49 911 65078-65066