Anchor Points Reactive Potential For Bond-Breaking Reactions

We present a new method for fitting potential energy surfaces in molecular-mechanics-like internal coordinates based on data from electronic structure calculations. The method should be applicable to chemical reactions involving either bond dissociation or isomerization and is illustrated here for bond dissociation, in particular the breaking of an O-H bond in methanol and the breaking of an N-H bond in dimethylamine. As compared to previously available systematic methods for fitting global potential energy surfaces, it extends the maximum size of the system than can be treated by at least an order of magnitude.