[lammps-users] surface energy of diamond by AIREBO

Dear LAMMPS users and Steve,

I am checking the AIREBO potential whether it is correctly implemented in LAMMPS. For that I calculated basic bulk properties such as the surface energy of the diamond.

Generally the surface energy of diamond (001) plane is larger than that of (111) plane:

theoretically: 9.2 J/m^2 for (001) and 5.3 J/m^2 for (111)

computationally*: 5.0 J/ m^2 for (001) and 1.3 J/m^2 for (111)

*by using Brenner potential from Science Letters 259 (1991) L714-L718

However I obtained larger surface energy for (111) (17.5 J/m^2) than (001) (10.9 J/m^2) surface with the REBO energy only (switched off both LJ and Torsional energy term in the AIREBO). I think this is wrong. The number can be deviated but the general trend should be followed. Below is my input script. Please take a look and let me know what would be not correct.

Thank you so much.