INDO and MINDO/3 atom-in-molecule polarizabilities

The INDO and MINDO/3 finite-perturbation algorithms for computing the molecular static electric dipole polarizability tensor aM were applied to obtain a set of atom-in-molecule polarizability tensors ai useful for crystal lattice energy calculations. The decomposition of aM into the ai must yield symmetric tensors, and requires the invention of a scheme to assign bond moments for closed-ring atoms. The resulting ai depend on the molecular geometry and seem to describe local bonding effects rather well. They underrate the polarizability perpendicular to covalent bonds (because of a lack of polarization functions in the INDO and MINDO/3 basis set) but the MINDO/3 ai values are rather close to the atom polarizability tensors derived from experimental data by Applequist.