We propose to obtain accurate expressions for the short range intermolecular interaction energy, as far as possible in terms of one-molecule properties, and to develop a database of such properties that can be used in intermolecular potentials for new systems . The repulsive interaction energy between two molecules will be obtained from the repulsion between each molecuLe and some suitable test particle, calculated taking correlation corrections into account. A model orientation-dependent atom-atom potential will be fitted to the calculated energy. A suitabLe combining rule will be used to obtain the molecule-molecule interaction from molecule-probe and probe-probe interactions, and it will then be refined using perturbation calculations for the complex. In this way we can compile a database of potentials that can be used in any of the applications where the current generation of crude
point-charge/Lennard-Jones potentials are used, but that should give much better results.