Groups of atoms, say two of them, can have angular momentum as a group, but only because they individually have linear momentum and are bound together through a force that causes them to pull on each other so that the group as a whole spins. Does it make sense to talk about the angular momentum of a single atom?
I was trying to understand how a photon's angle of reflection is determined, since there really is no such thing as a continuous surface. There are just groups of atoms. So, what's the difference of the interaction when a photon hits a single atom or hits an atom is surrounded by (8) other atoms in a 2-D arrangement (i.e. a 3x3 grid)?