Fix QEq

Regarding the fix qeq/comb and fix qeq/reax:

The doc page gives examples of both. For qeq/comb, it appears to equilbrate charge every 10 time steps (which I find to be sufficient in my simulations), the qeq/reax doc page has charge equilibration every time step. Can both qeq’s be done only every 10 timesteps, or does the one for reax require higher frequency?

I am currently running simulations with ReaxFF but as known by everyone here, it is very computationally expensive and thus it will take several days before I can make any conclusions. Has anyone had experience in charge equilibrating more frequently than every time step?


It really depends on your application, i.e., structure, temperature, strain rate, reactivity, etc. There is no hard-set rules, and you have to figure that by rigorous comparisons.

By the way, being able to make conclusions within days seems to be very satisfying.