SKM 2023 – scientific programme
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O: Fachverband Oberflächenphysik
O 17: Focus Session: Frontiers of Electronic-Structure Theory II (joint session O/HL)
O 17.6: Talk
Monday, March 27, 2023, 16:45–17:00, TRE Ma
Exact sum-rule approach to polarizability and asymptotic van der Waals functionals -- derivation of exact benchmarks — •Alberto Ambrosetti1, John Dobson2, Matteo Ricci1, and Pier Luigi Silvestrelli1 — 1Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, via Marzolo 8, 35131, Padova, Italy — 2Nanoscale Science and Technology Centre, Griffith University, Nathan, Queensland 4111, Australia
Using a sum-rule approach we develop an exact theoretical framework for polarizability and asymptotic van der Waals correlation energy functionals of isolated objects[1]. The functionals require only monomer groundstate properties as input. Functional evaluation proceeds via solution of a single position-space differential equation, without the usual summations over excited states or frequency integrations. Explicit functional forms are reported for reference physical systems, including atomic hydrogen and single electrons subject to harmonic confinement, and immersed in a spherical-well potential. Direct comparison with the popular Vydrov-van Voorhis density functional shows that this performs best when density decay occurs at atomic scales. The adopted sum-rule approach implies general validity of our theory, enabling exact benchmarking of van der Waals density functionals, and direct inspection of the subtle long-range correlation effects that constitute a major challenge for approximate (semi-)local density functionals.
[1] M Ricci, PL Silvestrelli, JF Dobson, A Ambrosetti J. Phys. Chem. Lett. 13, 8298-8304