problem with hex structure

Hi everyone.

I wanted to simulate argon flow between graphite plates which have hexagonal structure. Argon has FCC structure which I should model it in 3d Dimension but hex should model in 2d dimension.

How can I model hexagonal in such case?, because if i set dimension to 3d and I use fcc and hex lattices,

Lammps errors that i can’t use hex in 3d dimension.

Could anyone help me?

Thanks a lot.

The lattice doc page explains that "hex" in LAMMPS lingo
is a 2d lattice. So you cannot use it in a 3d simulation. Maybe
you want "hcp" which is a 3d lattice. If what you want to
do is populate a 2d plane of atoms within a 3d simulation then
you can simply use a 3d lattice (e.g. fcc or hcp) and define
a thin planar-like region to fill with atoms. Using a custom
lattice you should be able to define a 3d lattice which gives
you what you want when you take a 2d slice of it.