[lammps-users] temperature problems in reaxFF

I’m interested in the Si oxidation process.

I used the reaxFF to describe the interactions between Si-O.

The behavior of oxidation, eg. formation of amorphous silica, charge transfer, penetration of oxygen into oxide, and so on, seemed to be fine.

However, I found some problems when I give additional force to the oxygen molecules.

In the thermo output, the temperature of oxygen increased up to 40,000 K and, of course, the kinetic energy of oxygen increases too high.

I’ve tried to do various ways to give kinetic energy to oxygen atoms, such as velocity set command, fix addforce, fix drag, fix setforce, etc.

The result, showing abnormal temperature, was the same all the time.

I have no idea why the temperature increases abnormally.

If you have good ideas, give me some advices.

If you're giving a kick to O atoms, their temperature will
go up. If you reduce the size of the kick it should go up less.
Does that happen? You may also need to use a smaller timestep.