1. Obviously, the best ``potential'' is found from a quantum mechanical study. These ``ab-initio'' or first principle potentials can only be applied to systems of very limited size, and extremely limited time development.

  2. Next best is something in the spirit of ``tight-binding'' molecular dynamics, where quantum mechanical effects are included within this approximation.

  3. Manybody potentials assembled from first principle results and experimental measurements are in wide use for calculations with thousands of particles for times sufficient to observe many phenomena. Excellent agreement between manybody potentials and first principle results can be found, see one example.

  4. The weakest potentials for general use are the simple potentials, such as Lennard-Jones. These are great for argon, but do not give a good approximation to semiconductors or ceramics.

  5. For carbon modeling we used the potentials of Tersoff [Phys.Rev.Lett. 61 (1988) 2879] and Brenner [Phys.Rev.B 42 (1990) 9458]

  6. For vanadium we used the Embedded Atom Potential of Finnis and Sinclair and for aluminium we used Ecolessi-Adams potentials.