A Local Representation Of The Dielectric Response Function

The screened dielectric response function ($\chi$) is a fundamental physical quantity that captures the many-electron correlation effects, key to the accurate description of van der Waals dispersion interaction in the ground state and a range of excited state properties. Although $\chi$ is non-local by definition, a real space partition of $\chi$ onto local structural motifs can help us gain further physical insight into, e.g., effective local screening properties. Because the construction of bare response function, $\chi_0$, is associated with the product of electron - hole orbitals, standard localization procedures for electron wave functions can not be directly applied. In this work, we propose a new method to decompose $\chi_0$ into contributions from local response functions. Exemplary results of finite and bulk systems are discussed.