Interatomic Potentials for Silicon Structural Energies

We develop two- and three-body classical interatomic potentials that model structural energies for silicon. These potentials provide a global fit to a data base of first-principles calculations of the energy for bulk and surface silicon structures which spans a wide range of atomic coordinations and bonding geometries. This is accomplished by use of a new "separable" form for the three-body potential that reduces the three-body energy to a product of two-body sums and leads to computations of the energy and atomic forces in $n^2$ steps as opposed to $n^3$ for a general three-body potential.