Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.91: Poster

Tuesday, April 1, 2014, 18:30–22:00, P1

RPA correlation energy calculated within the FLAPW method — •Markus Betzinger, Christoph Friedrich, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

According to the adiabatic-connection fluctuation dissipation theorem the exchange-correlation energy of Kohn-Sham density-functional theory (KS DFT) is expressed in terms of the many-electron density response function. Approximating the latter by the random-phase approximation (RPA) leads to the RPA correlation energy of KS DFT. It has been demonstrated that the RPA describes covalent, ionic, and vdW bonded systems equally well. The main obstacle in calculating the RPA correlation energy is the slow convergence of the KS response function in terms of the orbital basis set and the number of unoccupied states. We present an extension of the recently developed incomplete-basis-set correction (IBC) [1] to the frequency domain, which enables to compute the RPA response function accurately. The IBC, which is based on the FLAPW method, comprises a basis response term that lies in part outside the Hilbert space spanned by the original basis. The convergence of the RPA response function in terms of basis-set size and number of unoccupied states is considerably accelerated by the IBC. We show first results for RPA lattice constants and bulk moduli calculated for a set of prototype materials.
This work is supported by the Helmholtz Postdoc Programme.
Phys. Rev. B 88, 075130 (2013); ibid. 85, 245124 (2012)