Abstract
Typical empirical bond-order potentials are short ranged and give ductile instead of brittle behavior for materials such as crystalline silicon or diamond. Screening functions can be used to increase the range of these potentials. We outline a general procedure to combine screening functions with bond-order potentials that does not require refitting any of the potential's properties. We use this approach to modify J. Tersoff's, P. Erhart and K. Albe's, and T. Kumagai 's Si, C, and Si-C potentials. The resulting potential formulations correctly reproduce brittle materials' response and give an improved description of amorphous phases.