Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 106: Frontiers of Electronic Structure Theory: Many-Body Effects, Methods (organized by O)
TT 106.9: Vortrag
Donnerstag, 19. März 2015, 17:15–17:30, MA 004
Accurate, efficient localized resolution of identity of the Coulomb operator across the periodic table — •Arvid Ihrig1, Jürgen Wieferink1, Igor Ying Zhang1, Patrick Rinke1,2, Volker Blum1,3, and Matthias Scheffler1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany — 2Aalto University, Helsinki, Finland — 3Duke University, Durham, USA
A key component of advanced electronic structure methods is the explicit evaluation of the Coulomb operator. The corresponding four-center integrals can be solved with a “resolution of identity” (RI) approach for numeric atom-centered orbitals, as they are used in, e.g., FHI-aims [1]. In RI, basis function products are expanded in an auxiliary basis. The complete auxiliary basis is used for “RI-V”, the most accurate and most commonly used RI. We developed a localized RI (“RI-LVL”), which expands the products only in the subset of those auxiliary functions centered on the same atoms as the basis functions. This approach yields a superior scaling with system size, both in terms of computational time and memory requirements. At the same time it also retains the accuracy of the RI-V, as we have shown for HF, MP2, PBE0 and RPA calculations. The systems we investigated include weakly interacting molecular dimers (S22 test set) as well as TiO2, Cu, and Au clusters. In all test cases we found that RI-LVL reproduces RI-V very accurately. Even for RPA-calculations of gold with very large basis sets the deviation to RI-V is only ∼1.5 meV per atom. [1] V. Blum et al., Comput. Phys. Commun. 180, 2175 (2009).