Regarding Equilibriation of Active Systems

Dear User’s,

If I have a driven system of particles, I mean like a collection of particles which are able to propel by the addition of an external force (using fix_addforce) in an environment of passive particles. So how can I ensure that my system is equilibrated? I am doing an energy minimization (using minimize command). But as I am using an external force on a particular type of particles, those particles are always out of equilibrium, So is there a way to know about the equilibration of the whole system in LAMMPS? How can I do an equilibration in such cases?

Any comments and suggestions would be highly appreciated…

Thank You


minimization != equilibration

equilibrium is reached, when the ensemble average of energies, pressure and other properties (during MD) doesn’t change any more but is approaching a constant value.

please look up more details in a proper text book on MD and statistical mechanics.


of course, if you have a driven system, i.e. you add energy to the system, you have to have some dissipation mechanism that removes energy from the system (e.g. a thermostat) so you get a dynamical equilibrium. otherwise, no equilibrium is possible.