[gmx-users] Electrostatic Potential in confinment

[David van der Spoel]

On 17/07/16 20:39, Alireza Moradzadeh wrote:
> Dear All,
>
> I am using GROMACS to study Electric Double Layer in confinement. I add 3
> times of slab length as vacuum to my system in the z-direction and I use
> PME with Ewald-geometry :3dc to treat electrostatic. My walls are
> oppositely charged. Just to give an idea of what I am doing.
>
> I use gmx potential to calculate electrostatic potential across the
> channel, but in the middle part of channel, where it is supposed to be bulk
> fluid, therefore, electrostatic potential should be constant I saw a linear
> drift. instead of a plain line. Can anybody give me an idea what can be
> wrong in my simulation.
>
> Best Regards,
> Alireza Moradzadeh
>
If I understand you correctly you have oppositely charged plates which 
therefore provide a constant electric field. If you integrate the field 
you should therefore get a linearly increasing potential, right?

-- 
David van der Spoel, Ph.D., Professor of Biology
Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205.
spoel at xray.bmc.uu.se    http://folding.bmc.uu.se