Advanced concepts within the automated generation of multi-dimensional potential energy surfaces

• Applicant: Professor Dr. Guntram Rauhut
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280537713

The accurate calculation of multi-dimensional potential energy surfaces for molecules and molecular clusters by means of quantum chemical methods, e.g. coupled-cluster approaches, is a computationally very demanding task and a field of active research. However, it is not only the generation of these surfaces itself, which needs special attention, but also its representation, which has significant impact on subsequent calculations. Within the framework of the ab initio calculation of anharmonic vibrational spectra based on variational methods like vibrational self-consistent field (VSCF) theory or vibrational configuration interaction (VCI) theory, techniques for the improved generation and representation of potential energy surfaces are proposed, which allow for faster and more robust vibrational structure calculations. These techniques comprise a tensor decomposition of the analytical representation of potential energy surfaces, the introduction of permutational symmetry to localized normal coordinates and other minor aspects. Due to the gained acceleration of such calculations, even larger molecules can be computed, which shall be demonstrated for a series of molecules, e.g. boranes and dicarbaboranes.

• DFG Programme: Research Grants