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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 15:14:43 -0500

In order to do this, I had to change the dimension to 3d and changed the lattice from sq to sc and boundary p p f. Since I cannot enforce2d in a 3d simulation, how do I zero out forces and velocities in z direction?



On 6 July 2017 at 13:29, Axel Kohlmeyer <akohlmey@...24...> wrote:
On Thu, Jul 6, 2017 at 2:27 PM, John Smith <johnson21smith@...24...> wrote:
> 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?

please see kspace_modify slab.

axel.

>
> 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@...24...  http://goo.gl/1wk0
>> College of Science & Technology, Temple University, Philadelphia PA, USA
>> International Centre for Theoretical Physics, Trieste. Italy.
>
>



--
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.