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Re: [lammps-users] Regarding interaction energy between copper and carbon dioxide
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Re: [lammps-users] Regarding interaction energy between copper and carbon dioxide


From: Axel Kohlmeyer <akohlmey@...24...>
Date: Sat, 1 Jul 2017 08:33:15 -0400

On Sat, Jul 1, 2017 at 5:37 AM, Zeeshan Ahmed <zeeshan.ahmed@...5589...> wrote:
> Dear All,
>
> I am trying to find the interaction energy between copper and carbon
> dioxide. There are many mixing rules available for that like LB mixing rule.
> But the problem with LB mixing rule is that it sometimes overestimates the
> potential parameters. So, to verify that I did find energy interaction
> between copper and carbon dioxide molecule.
>
> But in the lammps data file I have to give interaction parameters separately
> like (C-O, Cu-C and Cu-O interactions). Do the Carbon and oxygen
> interactions are different with copper when they are in a molecule? Or are
> they same  if I calculate Cu-C, Cu-O and C-O interactions separately? Any
> kind of help is appreciable. Thanks

interaction energies are an input parameter to classical MD
simulation, and interaction potentials are usually not very
transferable, i.e. only valid for a specific chemical environment or a
limited range of boundary conditions (temperature, pressure).
parameters derived from mixing rules are even less reliable, and
mixing rules are differently well applicable to different situations.

thus, if you want to compute these interactions with only the elements
(and geometry) as input parameters, you have to do quantum chemical
calculations.

FWIW, in the data file, you can give per atom type non-bonded
parameters (Pair Coeffs), which is mostly applicable to (bio)molecular
force fields, and as per pair of atom types parameters (PairIJ
Coeffs).

axel.

>
> Regards,
> Zeeshan Ahmed
> PhD Student (Mechanical Engineering)
>
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-- 
Dr. Axel Kohlmeyer  akohlmey@...24...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.