[gmx-users] 3dc warning

[Eric Smoll]

Hello Gromacs users,

I am using version 2018.1.

I have a system in an infinite slab configuration (periodic in the x and y
dimensions; in the z dimension, the atoms are permanently confined to 1/3
of the unit cell length with the remainder vacuum).

I am interested in simulating the system with 3D PBC and PME. Since I am
only interested in the behavior of a single infinite slab, interactions
between images of the slab in the z-dimension are unwanted. The 3dc
correction seems like a useful way to increase the realism in my
simulations.

However, grompp generates a warning: "With PME and ewald_geometry = 3dc you
should use pbc = xy"

As I understand it, 3dc is a correction for periodicity in the z-dimension.
Is pbc=xyz inappropriate?

Best,
Eric