I am using the LAMMPS version of 29Sep2021 to do a MC/MD simulation and attach my input script below. I used NVT ensemble and atom/swap to fix the system. I found that atom coordinations shift a lot after the MC swap (by seeing the dump.pos.0 and dump.pos.400000). Is there any way to do MC swap on the rigid lattice sites?

dump.pos.0.dat (118.9 KB)
dump.pos.400000.dat (123.4 KB) (1000 Bytes)

Thanks for any suggestion.


Your description is not very helpful in understanding what your problem is. Just providing the files and hoping for people to figure it out on their own is not likely to get you any help. As a basic principle: the better the description, the easier to understand the problem, the better your chances to get good and useful help. Remember that people here do not read minds and have no idea about what is your research project and what are the specific goals of your simulation.

Thanks for the reminding. In fact, I am trying to run a MC/MC simulation to decrease the potential energy of a random fcc alloying system. Initially atoms in random fcc system were assigned in rigid sites (inner coordinates are fixed), and after 400000 runs of MC/MD steps, atom coordinates were shifted away from rigid sites. So I was wondering if there is any way to put atoms back to the rigid sites?


The words you use make no sense to me, for example the term “rigid site”, or “inner coordinates” or “were fixed”.

So basically your additional explanation does not really improve on your original post and for the most part is the same with only a few details added.