Konrad Marti
PhD Thesis 2012, M. Reiher group
“New Electron Correlation Theories and Haptic Exploration of Molecular Systems”
In transition metal catalysis, the precise characterization of the relative energies is of paramount importance. In particular, it is still a challenging task to predict energy differences between states of different spin accurately using a wide variety of modern standard quantum chemical methods. The encouraging results of the density matrix renormalization group (DMRG) algorithm for complicated molecular electronic structure theory stimulated our research in this direction. We describe how the concept of quantum information entropy can efficiently be exploited and cast into an algorithm which aims to improve the convergence of the DMRG optimization. The new code is employed to describe spin splitting in methylene and ozone, as well as the high-spin ground state of a transition metal compound.
Finally, we present a new way of analyzing potential energy surfaces of chemical reaction mechanisms by means of a haptic exploration. The haptic methodology is shown to allow chemists to physically experience the quantum mechanical forces acting on reactants, to actively influence the chemical reaction, and to probe different reaction channels. The haptic machinery is demonstrated at the example of the protonation of a water molecule.