Prof. Dr. Richard Dronskowski
Chair of Solid-state and Quantum Chemistry
Chair of Solid-State and Quantum Chemistry
Welcome to the Chair of Solid-State and Quantum Chemistry at RWTH Aachen University, Europe's largest Technical University dating back to the year 1870. The following pages are intended to offer you a short overview of our research and teaching activities in the fields of solid-state and quantum chemistry. If you are interested in these exciting chemical disciplines, you have come to the right place. Stay with us! Don't go away!
HOT: LOBSTER goes Quantum ESPRESSO
We have performed an in-depth study of the chemical bonding in manganese oxide (MnO) and carbodiimide (MnNCN) from correlated spin-polarized density functional calculations. The chemical-bonding data were produced using the LOBSTER package, which has recently been enabled to process PAW-based output from Quantum ESPRESSO. Our results show that the antiferromagnetic ground states of MnO and MnNCN are similar, in agreement with experiment; also, MnNCN is more covalent than MnO. In addition, COHP analysis evidences that adopting the ground-state magnetic structures by MnO and MnNCN makes the cation-anion bonds optimized and annihilates obvious instability issues, that is, the existence of antibonding states in the vicinity of the Fermi level.
HOT: Two-dimensional Rietveld refinement of POWGEN data
The method of angular- and wavelength-dispersive (= 2D) Rietveld refinement is an emerging tool for the analysis of neutron diffraction data measured at TOF instruments with large area detectors. We elaborate on the necessary steps to perform such technique using the POWGEN instrument as an example. A dataset measured on a standard diamond sample is used to extract the profile function, and the variation of reflection width with 2θ and λ can be expressed by the standard equation for the instrumental resolution, which yields a substantially more fundamental approach to the peak shape. Geometrical considerations of the POWGEN instrument and sample effects lead to values for Δθ, Δt and ΔL that yield a very good match to the extracted FWHM values and allow for the final 2D Rietveld refinement.