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Re: [lammps-users] Difference in results for atomstyle charge and dipole
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Re: [lammps-users] Difference in results for atomstyle charge and dipole


From: John Smith <johnson21smith@...24...>
Date: Thu, 6 Jul 2017 13:27:15 -0500

I looked into the documentation and updated the pair_style to lj/cut/dipole/long to account for dipole-dipole interactions. I also changed from 'fix nve' to 'fix nve/sphere update dipole'. The documentaion said that I need to include

kspace_style ewald/disp 1e-4

But I am getting an error that that command cannot be used in a 2D simulation. How do I effectively make this into a 3D simulation and get the same results? Or can is there a workaround to getting the above command working in 2d?

Thanks,
John

On 5 July 2017 at 18:05, Axel Kohlmeyer <akohlmey@...24...> wrote:
On Wed, Jul 5, 2017 at 6:39 PM, John Smith <johnson21smith@...24...> wrote:
> Hello,
>
> I am attaching two input scripts, one with a mixture SRD of style charge
> (initial charge set to 0.0) and the other with a net dipole of 1.0 (in
> reduced lj units). I expected to see an effect due to electric field on the
> system in the case of dipole, but I am not able to observe any difference
> between the results of the two runs. I am also attaching the graphs for
> vacf, msd and diffusion coeffcient calculated using msd.
>
> I have used fix efield, but I am not sure if it is being called?

as the fix efield documentation states, fix efield adds a torque to
particles with a (point) dipole.
however, there is nothing in your input, that is in any way reacting
to this torque (or to the dipole outside of fix efield).

axel.

> Any advice please?
>
> Sincerely,
> John
>
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--
Dr. Axel Kohlmeyer  akohlmey@...43...4...  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.