First-principles approach to dielectric response of graded spherical particles

We have studied the effective response of composites of spherical particles each having a dielectric profile which varies along the radius of the particles. We developed a first-principles approach to compute the dipole moment of the individual spherical particle and hence the effective dielectric response of a dilute suspension. The approach has been applied to two model dielectric profiles, for which exact solutions are available. Moreover, we used the exact results to validate the results from the differential effective dipole approximation, recently developed to treat graded spherical particles of an arbitrary dielectric profile. Excellent agreement between the two approaches were obtained. While the focus of this work has been on dielectric responses, the approach is equally applicable to analogous systems such as the conductivity and elastic problems.