# Non-local description of electron-positron correlation effects

**Datum:**13 april 2016

**Locatie:**University of Antwerp - Campus Groenenborger - Room U.241 - Groeneborgerlaan 171 - 2000 Antwerpen

**Tijdstip:**16 - 17 uur

**Korte beschrijving:**Condensed Matter Theory seminar presented by Vincent Callewaert

**Abstract**

Presently, the most reliable first-principles calculations of positron annihilation properties in solids are based on a two-component density functional theory. Correlation effects between the positron and electrons are usually described with a local density or generalized gradient approximation. These have proven to yield reliable result for the description of positrons in bulk materials. However, in systems where the electron density is highly anisotropic, such as surfaces, these (semi-)local descriptions break down.

In this talk, Vincent Callewaert will show why these descriptions fail and how one can solve this problem. In particular, the talk will focus on the weighted density approximation which provides a non local description of the electron-positron correlation and does not rely on empirical input.

Vincent Callewaert, CMT group, UAntwerpen

**Contact e-mail:**lucian.covaci@uantwerpen.be

**Url:**http://cmt.uantwerpen.be