changing atom type and group during dynamics

Dear developers and users,

I am a new user of lammps.
I have a bit peculiar system to simulate, and I’m facing some problems in introducing some specific features in my input.
In detail:

I need to simulate, with LJ potentials, the reaction of an atom (type 2) that binds to other atoms of different type (type 1)
So I created two groups of particles, group 1 of type 1 , group 2 of type 2.
When a particle X of type 2 arrives within a certain radius around particles of type 1, it has to change nature and to become of type 1.
It has to bond to other particles of type 1.
The particle X has also to acquire all properties of type 1 atoms, including any kind of interaction with particles of its own
new type and of its previous type.

Could you tell me the easiest way to model such behaviour?

Thank you for any kind of help/suggestion you could give me,
best wishes

If you want to create a bond and change the type of the atom,
you can look at the fix bond/create command. If you don’t want
to create a bond, but just change the type, e.g. based on some
distance criterion, then I think you would have to write a new
fix to do this. It wouldn’t be hard to do.