Analytic bond-order potentials for multicomponent systems

Classical interatomic bond-order potentials (BOPs) have previously been obtained by coarse-graining the quantum-mechanical electronic structure within the chemically intuitive reduced tight-binding (TB) framework. This paper generalizes the reduced tight-binding approximation to the case of multicomponent sp-valent systems, thereby allowing a rigorous derivation of expressions for the σ and π bond orders within chemically heterogeneous situations. The close link between the different bond-order potential parameters and different physical properties is illustrated for the particular choice of Goodwin–Skinner–Pettifor (GSP) radial dependences for the repulsive pair potential and two-centre bond integrals.