Creation of crystall structure of silicon carbide using pair_style tersoff/zbl ...for radiation simulation

The atom ID is something you assign in a data file,
or you can choose an atom from your "create atom" system
by specifiying it in some other way, e.g. by defining a small
region with one atom in it. Once you have the atom in a
group, it is easy to dump just that atom or compute various
quantities on that "group", e.g. pot eng, velocity, etc.