Reexamining a local, real-space approach to screening

Various many-body perturbation theory techniques for calculating electron behavior rely on W, i.e., the screened Coulomb interaction. The exact screening requires complete knowledge of the dielectric response of the electronic system. As a simplification, calculations often begin with the RPA or random phase approximation. However, even at the RPA level the calculations are costly and scale poorly with system size. A local approach has been shown to be efficient while maintaining accuracy [1]. We present improvements to this scheme, including reconstruction of the all-electron character of the pseudopotential-based wave functions, improved scaling with system size, and a parallelized implementation. We discuss applications to Bethe-Salpeter calculations of core and valence spectroscopies.

[1] E. L. Shirley, Ultramicroscopy 106, 986 (2006)