specifying the size of atoms

Hello dear

i want to simulate water and nano fluid cu in a fcc lattice…water is base fluid and cu is a region (sphere or box)in the center of lattice (between water)

is there any command to specify the size/diameter of atoms (cu or h2 or o2)in input code of lammps?

i appreciate any help.



For an all-atom model, the “size” of an atom
is typically the sigma in its Lennard-Jones parameters.