[lammps-users] Adding an atom type

Dear Steve, lammps users,

Is it possible to add an extra atom type in the input script after reading the data from a restartfile using read_restart command? All of its other attributes like mass, epsilon, sigma can be defined later on in the script.

After looking into various options, it seems like create_box command let you define no. of atom types in the system. This command also needs a pre-defined region. However, by this time, I have already read the restartfile. So, I am not sure if I should use region command with EDGE option or INF option (if that makes sense).

Any info will be highly appreciated.


Create_box and read_restart and read_data are mutually exclusive commands,
each of which defines the number of atom types.

You only do one of the 3. If your restart file wasn't created with
enough atom types, I think you're stuck. You could massage it
to have more (empty) types, but you'd have to know the binary format
at a lo-level. You could convert it into a data file via restart2data, then
just add the extra types in the data file by hand (which is text).

Ideally, you would have written the restart file with extra (empty)
types, using the create_box command as you said below,
in the initial input script.