A local interpolation scheme using no derivatives in quantum-chemical calculations

A scheme using interpolant moving least squares (IMLS) combined with Shepard interpolation is proposed to describe potential energy surfaces (PES). This scheme does not require any derivatives in quantum-chemical calculations to construct a PES, in contrast to previously developed schemes based on Shepard interpolation alone. In addition, the scheme retains the advantages of local interpolation schemes. Application is made to an analytical surface for the H3 system.