Photophysics of organic photostabilizers: ab initio electronic-structure and quantum-dynamics calculations

• Applicant: Professor Dr. Wolfgang Domcke
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: from 2006 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 32931736

The aim of this project is the investigation of the dynamical processes which account for the functionality of organic photostabilizers, using the tools of computational chemistry. Ab initio electronic-structure theory will be employed to determine the essential features of the excited-state and ground-state potential-energy surfaces. A primary goal is the identification and characterization of conical intersections of the energy surfaces of the lowest exited singlet state (S1) and the electronic ground state (S0). These conical intersections serve as photochemical funnels for the ultrafast deactivation of the excited state. The dynamics of the S1¿S0 radiationless decay processes at the S1-S0 conical intersections will be investigated with time-dependent quantum wave-packet methods. The theoretical studies will be focused on three intramolecularly hydrogen-bonded aromatic systems for which an extensive set of experimental data is available: ohydroxybenzaldehyde, salicylic acid and 2-(2 -hydroxyphenyl)benzotriazole (TINUVIN). Summary of the interaction: The ab initio electronic-structure calculations will be performed in the group of A. L. Sobolewski in Warsaw. This includes the exploration of exited-state potential-energy surfaces, the determination of reaction paths and conical intersections, as well as the calculation of ab initio energy data on large grids in nuclear coordinate space. Multidimensional multi-sheeted analytic potential-energy functions will be constructed in the group of W. Domcke in Munich, using the ab initio-data provided by the Warsaw group. The time-dependent quantum reaction dynamics computations will be performed with the programs available in the Munich group. Much of the exchange of information will occur by email or file transfer. To broaden the education of the students and/or postdocs, these coworkers will visit the respective partner group once per year.

• DFG Programme: Research Grants
• International Connection: Poland
• Participating Person: Professor Dr. Andrzej L. Sobolewski