Computational model setup for spectroscopic quantification of reactive mixtures using ab initio molecular dynamics

• Applicants: Professor Dr. Kai Leonhard; Dr.-Ing. Jörn Viell
• Subject Area: Technical Thermodynamics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 537592518

Quantitative spectroscopy helps to optimize chemical engineering processes. It relies on well-calibrated models to link spectra to species concentrations. The calibration can be tedious or impossible for reactive systems due to short-lived or instable components. Our recently developed combination of Indirect Hard Modeling (IHM) with ab initio molecular dynamics (AIMD) simulations allows for model calibration without experiments, thereby enabling model setup for short-lived compounds in reactive systems. Still, current limitations of AIMD-IHM pertain to species even unstable in simulations, accessible system sizes and times, and strongly overlapping peaks. In this proposal, we plan to overcome the current limitations by developing and using machine-learning methods as well as advanced simulation and analysis techniques. The resulting AIMD-IHM method will be applied to dissociation equilibria of itaconic and citric acid and of phosphoric and sulphuric acid over wide pH ranges. New Raman and titration experiments will validate the computational model. The dynamic system of fatty acid oxidation with hydrogen peroxide involves a number of short-lived intermediates. Using AIMD-IHM, their concentration changes with time and space can be recorded, so that data on reaction kinetics and mass transfer are made accessible from the spectroscopic measurements. At the end of the project, we expect a new methodology that will allow obtaining real-time reaction data by quantitative spectroscopic analysis of chemical systems that are inaccessible today.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr.-Ing. Hans-Jürgen Koß