The relevance and limitations of the Clausius-Mosotti relation in quantum systems

Publisher Website
Google Scholar
Abstract
A parameter is introduced which corresponds to the ratio of importance of band-structure effects to electron-hole correlation in calculating the dielectric function. When this parameter is zero, that is with no hopping, a more detailed calculation is performed and two types of Clausius-Mosotti-like relations are found, depending on whether there are one or two electrons per site, the first of them corresponding to the classical one. The other contains an extra term which is related to singlet-triplet splitting. The case when the parameter is small but non-zero is considered and the dielectric matrix in perturbation theory is evaluated. The result is interpreted physically as being a corrected Clausius-Mosotti relation.