Bond dissociation Energy calculation

Hi all,

I am trying to calculate bond dissociation energy of BH/CH bond in orthocarborane molecule using reaxFF. What is the standard way to do this? I am trying keep fix all other atoms and only move the H atom back and forth and calculate the total energy. Is there any way to do this in lammps during the minimization process so that I can allow to move only one atom.

-Nirmal