09. Feb. 2012, 16:15 Uhr, Gebäude NW1, Raum H3
VORTRAG FÄLLT LEIDER AUS!
Prof. Dr. Matthias Scheffler, FHI Berlin, MPG
Dispersive or van der Waals (vdW) interactions are crucial for the formation, stability, and function of many molecules and materials. They typically dominate in regions where the overlap of electron densities is small, i.e., at medium to long interatomic distances. Interestingly, the commonly applied implementations of density-function theory (LDA, GGAs, hybrids) are completely lacking this vdW tail.
In this talk, I will review recent advances in electronic-structure theory; in particular, I will highlight the exceptionally accurate and truly parameter-free “exact exchange (EX) plus random- phase approximation to correlation (cRPA)” approach and recent corrections to cRPA. Furthermore, I will discuss approximations that are computationally more efficient and enable the treatment of large systems or long time-scale molecular dynamics. The main part of the talk deals with representative applications, e.g.,
• The noticeable role of vdW interactions in the cohesion of noble metals and semiconductors and in the intermolecular interactions in water and ice.
• Particular focus will be put on inorganic/organic interfaces, i.e., the adsorption of organic molecules at metals and semiconductors, and on tuning the workfunction of the inorganic substrate by molecular acceptors.
• Regarding biophysics, I will show that and how vdW interactions changes the conformational landscape, stabilize the helical hydrogen bond network compared to plain DFT-GGA calculations, and thus enhance the thermal stability of helical structures by several hundred K.