[gmx-users] potential profile with PBC

[Alex]

Hi all,

I have a perfectly well-behaved system that consists of a membrane in water
+ ions. Upon plotting the per-slice profiles (ion densities and potential:
https://www.dropbox.com/s/tl91lg0fu2u5lbc/profiles-1.jpg?dl=0) everything
looks great with one exception: the potential values are different at the
boundaries. There are no external fields in the system, nothing like that.
When choosing the group for the potential calculations, i select System.

This potential difference seems fundamentally wrong, given PBC. Any
suggestions?

Thanks,

Alex