Temperature and pressure parameters to simulate super critical water

I have 3 input files:

  • Minimization
  • Balancing
  • Production

I want to bring my reactive system (ReaxFF) to critical temperature and pressure conditions. My question is: from which stage (one of the input files) should I perform the temperature and pressure increase from standard conditions to my working conditions (647 K, 220 bar).

Isn’t that something you should be rather discussing with your adviser or supervisor?

Personally, I would set up and equilibrate the system to the desired conditions with a standard rigid water potential (SPC/E, TIP4P, TIP3P or similar) first and then remove or disable bonds and angles and switch to ReaxFF.

You also need to check that you have a ReaxFF parameter set that is suitable to modeling water at supercritical conditions.