[lammps-users] ReaxFF potential

Hello everybody,
Did anyone try simulating diamond cubic silicon bulk using reax potential. When I try to do basic simulation to find out cohesive energy, I get Cohesive energy of silicon as about 160 Kcal/mol, where as it is supposed to be 106 Kcal/mole. I even tried plotting the potential energy curve, I found that the depth of the well is not maximum at the equilibrium distance. Can anybody help me with this.
Regards,
Vas