I want to simulate a system having three components with ReaxFF in Lammps. I got the reaxff for all three components from literature. Now, how can I simulate my system with three different force fields in lammps.
Many people before you have asked how to merge reaxff force fields, please look for previous post in this forum. For example : ReaxFF hybrid force field
Long story short, the force field you create by mixing different ReaxFF files may not be valid, so a lot of care should be taken.
Simon
I would take out the “may” in this sentence. Without additional work and without having the expertise of parameterizing systems for ReaxFF, it is guaranteed that merging parameter files will give bogus results. Trying multiple instances of ReaxFF via pair style hybrid is much worse as you would also need to use pair-wise additive interactions between the different components and there is the added difficulty of how to consistently perform the necessary charge equilibration.
Bottom line: do you really need to use ReaxFF? We see a lot of people using it because it seems much easier to use than traditional force fields, where you have to assign force field types and partial charges to atoms, but that is just replacing the devil with Beelzebub, as the saying goes.