Hi Andrew,
Due to LAMMPS’ clever use of pointers, it is my understanding that you can change atom types as in fix bond/create and simply force a re-neighboring rather than packing/unpacking atom types. After glancing at fix bond/create though, it does appear to have slightly incorrect logic for updating both atom types. Though I haven’t tested this, the attached version should be moving in the right direction (added lines 526-531)
Thanks,
Jake
fix_bond_create.cpp (43.4 KB)