Empirical triatomic potential energy surfaces defined over orthogonal bond order coordinates

A new simple but realistic empirical representation of collinear triatomic potential energy surfaces is proposed and examined. The approach is based on the introduction of a novel system of orthogonal coordinates defined in terms of the bond orders of the two bonds. The potential surface is represented as an interpolation between the two asymptotic diatomic potentials along these coordinates. In addition to the two diatomic potentials the potential energy surface contains two empirical constants: A coordinate scale factor (which enters into the definition of the bond order via the Pauling relation) and an energy scale factor (which is roughly constant for a series of surfaces with a common central atom).