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

• Final Report Year: 2010

Final Report Abstract

The mechanisms of ultrafast excited-state quenching in hydrogen-bonded aromatic systems have been explored with ab initio electronic-structure methods and quantum wave-packet calculations. Reaction paths for the excited-state coupled electron-proton transfer process have been characterized for salicylic acid, tinuvin, dihydroxyindole, pyridyl-indole and the hydrogen-bonded pyrrole-pyridine complex. The existence of S1-S0 conical intersections, which can be accessed by photoinduced hydrogen transfer and torsion of active groups, has been demonstrated for salicylic acid, tinuvin, dihydroxyindole and pyridol-indole. The pyrrole-pyridine complex was selected as a model system for the study of the time-dependent dynamics of the excited-state quenching process. The non-Born-Oppenheimer nuclear dynamics has been simulated with time-dependent quantum wave packet methods, including the two or three most relevant nuclear degrees of freedom. The effects of the numerous additional weakly coupled vibrational modes have approximately been taken into account with a reduced density-matrix method (Redfield theory). The results provide insight into the microscopic mechanisms of excited-state quenching in hydrogen-bonded aromatic systems via an electron-driven proton-transfer process.

Publications

• Photophysics of intramolecularly hydrogen-bonded aromatic systems: ab initio exploration of the excited-state deactivation mechanisms of salicylic acid. Phys. Chem. Chem. Phys. 8, 3410 (2006)
  A. L. Sobolewski and W. Domcke
  
• Photophysics of organic photostabilizers: Ab initio study of the excited-state deactivation mechanisms of 2-(2’-hydroxyphenyl)benzotriazole. J. Phys. Chem. A 110, 6301 (2006)
  A. L. Sobolewski and W. Domcke
  
• Computational studies of the photophysics of hydrogen-bonded molecular systems. J. Phys. Chem. A 111, 11725 (2007)
  A. L. Sobolewski and W. Domcke
  
• Photoinduced electron and proton transfer in the hydrogen-bonded pyridine-pyrrole system. J. Phys. Chem. B 111, 6110 (2007)
  L. M. Frutos, A. Markmann, A. L. Sobolewski and W. Domcke
  
• Photophysics of eumelanin: ab initio studies on the electronic spectroscopy and photochemistry of 5,6-dihydroxyindole. ChemPhysChem 8, 756 (2007)
  A. L. Sobolewski and W. Domcke
  
• “Photoinduced nonadiabatic dynamics of aromatic molecules via conical intersections. Electronic-structure and quantum dynamics calculations”. PhD thesis, Technische Universität München, 2007
  Zhenggang Lan
  
• Photochemistry of hydrogen-bonded aromatic pairs: quantum dynamics calculations for the pyrrole-pyridine complex. Proc. Natl. Acad. Sci. USA, 105, 12707 (2008)
  Z. Lan, L. M. Frutos, A. L. Sobolewski and W. Domcke
  
• Role of vibrational energy relaxation in the photoinduced nonadiabatic dynamics of pyrrole at the 1πσ*-S0 conical intersection. Chem. Phys. 350, 125 (2008)
  Z. Lan and W. Domcke