Natural Bond Orbitals and the Nature of the Hydrogen Bond

The charge-transfer component of the energy of interaction between molecules has been a controversial issue for many years. In particular, the values reported from the use of the natural bond orbital analysis of Weinhold and his coworkers are several times larger than those obtained by other methods. I argue that these values are heavily contaminated with basis-set superposition error and are meaningless in the context of intermolecular interactions.