FOR 618:  Understanding the Aggregation of Small Molecules Using Precise Methods - Interplay between Experiment and Theory

• Subject Area: Chemistry
• Term: from 2006 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 13532987

The aggregation of molecules to form well-defined clusters up to macroscopic crystals is a fascinating phenomenon. However, details of this process are still not well understood. The weak intermolecular interactions leading to aggregation are difficult to investigate, both experimentally and theoretically. Until now, the prediction of the structure of molecule crystals is still an unsolved problem of chemistry, since especially the dynamic processes leading from the nucleation of a few molecules to the macroscopic crystal are not well understood. The goal of the Research Unit is to obtain a detailed understanding of aggregation phenomena - from dimers to larger aggregates as nucleation centres to extended molecule crystals. The aggregation of selected systems will be investigated in all details both experimentally and theoretically. This involves the determination of structures, energies and kinetic data on all levels of aggregation.
To achieve these goals the focus will be on small molecules, which allow for the quantitative determination of intermolecular interactions. The experimental techniques involve the spectroscopic characterisation of aggregates of small molecules in the gas phase, in molecular beams, in suprafluid ultra-cold helium droplets, as well as in inert gas matrices. Theoretical methods used involve the quantitative calculation of intermolecular interactions, quantum Monte Carlo simulations, and ab-initio molecular dynamics of aggregates. This broad spectrum of methods allows to investigate the aggregation in the gas phase, in molecular beams, in matrices, and in the solid state from single molecules to molecule crystals. Of importance is the quantitative determination of structural parameters and intermolecular interactions as well as the investigation of the dynamics of aggregations. The long-term goal is not only to understand aggregation, but to predict it quantitatively based on molecular properties.

• DFG Programme: Research Units
• International Connection: United Kingdom

Projects

• Ab initio-Molekulardynamik-Simulationen wasserstoffverbrückter Systeme: von der Aggregationskinetik bis zur thermischen Umwandlung (Applicant Doltsinis, Nikos L. )
• Die Aggregation kleiner Moleküle mit präzisen Methoden verstehen - Experiment und Theorie im Wechselspiel - Zentralprojekt (Applicant Sander, Wolfram )
• Herstellung und Charakterisierung von Kristallen und Cokristallisation kleiner Moleküle, vorrangig mit Acetylen, sowie von Pyridin- und Quinolinderivaten, basierend auf Deuterium- bzw. Fluor-Substitution (Applicants Boese, Roland ;  Merz, Klaus )
• Hochauflösende IR-Spektroskopie von ultrakalten molekularen Aggregaten (Applicant Havenith-Newen, Martina )
• Quanten Monte Carlo-Simulationen von molekularen Aggregaten bei endlichen Temperaturen (Applicant Marx, Dominik )
• Quantenchemische Untersuchungen molekularer Aggregate (Applicant Jansen, Georg )
• Schrittweise Aggregation kleiner Moleküle in Düsenstrahlen: Von Dimeren zu den Bildungsblöcken von Kristallkeimen (Applicant Kleinermanns, Karl )
• Wasserstoffbrückenaggregate und spezifische Solvatation - Untersuchung von Molekülen mit Heteroatomen, pi-Systemen und von offenschaligen Molekülen (Applicant Sander, Wolfram )

• Spokesperson: Professor Dr. Wolfram Sander