Using the semiempirical quantum chemical AM1 level of calculation, the model predicts the site-specific hydrogen bond acceptor strength from ground-state properties of the individual compounds. The model parameterization is confined to compounds with one acceptor site of the atom types: N, O, S, F, Cl, and Br that act as lone-pair acceptors, and π-electron (aromatic or conjugated) systems with the associated C atoms as particularly weak acceptors. The acceptor strength is expressed in terms of the Abraham parameter B and calculated from local molecular parameters, taking into account electrostatic, polarizability, and charge transfer contributions according to the Morokuma concept. The training set covered 383 compounds.
The model is ready for use. It is available as a particular piece of software. This program requires third-party software in order to run AM1.