Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 84: Correlated Electrons: (General) Theory

TT 84.1: Vortrag

Donnerstag, 3. April 2014, 09:45–10:00, HSZ 304

Uniform Electron Gas Approximation for the Second Order Screened Exchange Energy — •Felix Hummel and Georg Kresse — University of Vienna, Austria

The second order screened exchange (SOSEX) energy is the leading order correction to the random phase approximation (RPA) of the correlation energy. Computing the SOSEX contribution from the Kohn-Sham or Hartree-Fock orbitals scales like N⁵, making it considerably less practical than direct RPA, which can be implemented with an N⁴ or even an N³ scaling.

We approximate the exchange kernel by the respective kernel of the uniform electron gas. This allows for an approximation of the RPA+SOSEX energy with the favourable scaling of RPA. We believe, this captures the dominant part of the SOSEX contribution for many materials and we compare it with full RPA+SOSEX calculations.