Berlin 2014 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 18: Theory 3: Quantum Chemistry
MO 18.6: Vortrag
Donnerstag, 20. März 2014, 15:15–15:30, BEBEL SR144
Chromium: Benchmark for DFT — •Rolf Würdemann1 and Michael Walter1,2 — 1FMF, Uni-Freiburg, Freiburg, Germany — 2IWM, Freiburg, Germany
The 3d transition metal chromium is a hard case for DFT. While the neutral dimer has the shortest known metal-bond length, only long bonds are present in the bulk. We are investigating why this is the case and which functionals are able to describe these situations correctly.
The widely used local density approximation overestimates the binding energy of the neutral dimer and we show, that it is unable to predict the right ground state of the dimer cation.
Gradient corrected functionals give mixed results, even within the same functional family. where the functionals differ in the description of the exchange energy. We show that only the Bayesian error estimated functional (BEE) describes the chromium dimer in three different charge states correctly.
Based on these results we predict, that already for the chromium trimer only long bondlengths appear and thus rule out the so called “dimer-grow-path”.