The classical theory for a dielectric sphere can then be modified to treat ellipsoids oriented arbitrarily relative to an applied field, as described in Sec. S6. This model accounts for most of the differences between the polarizability components calculated with quantum mechanics and the predictions of an analogous spherical model, as shown in Fig. using PBE/DZP using conjugate gradient minimization, which resulted in increased bond lengths, but little overall reconfiguration. The polarizabilities of the particles along each Cartesian axis were then calculated as in Sec. 3.1, for both the re-optimized particles and the geometries without re-optimization.