I am using the LAMMPS REBO potential to study graphite and graphene. Initially I am trying to compute the cohesive energy to make sure it is consistent with the values found in the literature (books/journal publications). When I compute the cohesive energy I am getting a value of -7.789eV, compared to a value of -7.4eV from the literature. Additionally, in Brenner's 2002 paper �A second-generation REBO potential energy expression for hydrocarbons�, it is stated in Table 1 that a value of -7.4eV (atomization energy) was used in the fitting scheme of the potential for graphite.
Looking through the mail-list archives I see that the REBO potential in LAMMPS is not exactly the REBO potential in the 2002 Brenner paper, but it has been stated for all intents and purposes they can be regarded as the same. So I assume it was also fit to the -7.4eV value and should reproduce this value as well.
I was wondering if anyone else has tried computing the cohesive energy for a graphite or graphene system using the LAMMPS REBO potential and what their value was. Or if it is possible the discrepancy I am seeing is due to the slight difference between the LAMMPS REBO and the 2002 Brenner REBO.
Also I should add that when I found the cohesive energy using the full Airebo (REBO, LJ, TORSION) potential I calculated a value of -7.4eV for the cohesive energy, which is consistent with the literature. I am using the 31Aug11 version of LAMMPS.
Thanks for your time