Speaker: Andris Gulans (University of Latvia)
Title: High precision from augmented plane waves
Abstract: Electronic-structure codes implement density-functional theory in a number of different ways, and many of them rely on pseudopotentials. Such a feature improves performance, but also may undermine precision of calculations. A verification and systematic improvement of such approaches requires indisputable reference data. We address the ultimate reference issue by employing the full-potential linearized augmented plane waves + local-orbitals (LAPW+LO) method implemented in the code exciting. We calculate non-relativistic total energies of atoms and 55 molecules using LAPW+LO and unrelated numerical approach that is based on the multi-resolution analysis. The two methods agree within ~1 μHa/atom. For periodic systems, such reference tools for crosschecking the LAPW+LO method are currently not available. We therefore use variable atomic-sphere sizes in LAPW+LO to show that the 1 μHa/atom precision is attained also for solids in scalar- and fully-relativistic calculations.