CN+ reaxff + qeq

Dear LAMMPS users ,

I want to do MD simulation on three layers of a carbon nitride polymer to find stablest structure of that by Reaxff .

I have some questions about that :

1 - about fix qeq : what is the meaning of Taper radius ?!
Why does it care about cutlo ? I mean why it need “lo” and “hi” of cutoff ?

2 - about fix reax/c : when I use two different Reaxff and I get wrong results I have to look for other file again or it’s better for me to look for other reasons ?!

Thanks for your attention.