[lammps-users] adding group-ID to atoms within that group

Hi all,

I have a question regarding the handling of atoms within a certain group. Perhaps someone has an idea.

In my simulation I create several regions within the sample and asign the atoms within a region to the corresponding group. But when I write the atom coordinates, etc. to the dump-files (in my case CFGs) the information which group an atom is in are no longer available. I therefore had the idea to assign a new atom type (but same mass and potential as the initial type) to each group using the “set” command. However one has to specify all atom types in the “create_box” command first. Since the structure is read from a restart-file I can’t add another “create_box” command, so this route will not be possible most likely.

Is there another way to assign an integer value to atoms depending on the group they are in? I don’t necessarily need them to be of different atom type as long as I have a group specific identifier for each atom. It should look something like this:

atom-ID, type, xs, ys, zs, group-ID,…further properties

1 1 0 0 0.5 1…

2 1 0 0.5 0.5 1

3 1 0.5 0 0.5 1

4 1 0.5 0.5 0 2

5 1 0.5 0.5 0.5 2

Thanks in advance for your help.

Best regards,

Patrick