potential parameter test

I wanna to test the validation of potential parameters(ReaxFF) by MD which are still not refered by any thesis.
The materials are Al and a-Al2O3.
My lammps version is 2April11.
I get the elastic constants of Al and a-Al2O3 seperately. Elastic constants of Al coincide with experiment and DFT, while a-Al2O3 are almost half of the experiment. 'Cause this parameter is got by DFT, so I do not know how to explain it.
Does there any else method to check the validation of these parameters by LAMMPS?

Force-field fitting is an art unto itself. I suggest
you talk to Adri or another ReaxFF expert. Possibly
Aidan will want to comment.


2011/5/17 meihai3166 <[email protected]>:

ReaxFF potentials are not normally fit to elastic constants, so they can be
off by quite a bit. How accurate do you need the elastic constants? If you
are looking at complicated Al/Al2O3 structures, a factor of two error in the
elastic constants is probably not significant compared to other effects.