MOLECULAR-POLARIZATION MAPS AS A TOOL FOR STUDIES OF INTERMOLECULAR INTERACTIONS AND CHEMICAL-REACTIVITY

Maps for the interaction energy of acetone, pyrrole, furan, and pyridi ne with a positive unitary charge were computed using ab initio techni ques, together with their molecular electrostatic potentials at the sa me points. The difference between the interaction and electrostatic po tential maps yielded polarization maps for the molecules. Finally, map s for the interaction with a negative charge were obtained as the diff erence between the polarization and electrostatic potential maps. The calculations were carried out for three planes, 2 Bohr radii, 4 Bohr r adii, and 8 Bohr radii from the plane containing the heavy atoms for a ll the molecules. At larger distances, the interaction and electrostat ic maps resemble each other qualitatively; however, at shorter distanc es, where the polarization effects are more significant, the differenc es between the maps are notable. Interaction and polarization maps can be routinely evaluated for medium-sized molecules, and are likely to become an important tool in drug design and chemical reactivity.