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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 16:29:04 -0500

Thank you, it works now! I am getting a warning saying that kpsace is being invoked when there are no charges present. This is true since my input consists only of dipoles. Is it still necesary for me to use kspace_style?

Thanks,
John

On 6 July 2017 at 15:18, Axel Kohlmeyer <akohlmey@...24...> wrote:
On Thu, Jul 6, 2017 at 4:14 PM, John Smith <johnson21smith@...24...> wrote:
> 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?

velocity command and then fix setforce?

axel.

>
>
>
> 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
>> >> >
>> >> >
>> >> >
>> >> > ------------------------------------------------------------------------------
>> >> > Check out the vibrant tech community on one of the world's most
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>> >> > _______________________________________________
>> >> > lammps-users mailing list
>> >> > lammps-users@...396...sourceforge.net
>> >> > https://lists.sourceforge.net/lists/listinfo/lammps-users
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> 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@...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.