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Physics and Astronomy

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Susanne Ullrich, Associate Professor of Physics
243 103 lab
Biographical Information
Honors and Awards
  • Feodor-Lynen Fellow, Alexander von Humboldt Foundation, 2002-2004

Research Interests

Exploring Dynamics and Functionality of Biophotonic Molecules via Time-Resolved Spectroscopy

Biophotonic functions are triggered through light activation. The photoexcited biomolecules can undergo a variety of competing processes and the competition between these processes governs the selectivity, efficiency and reliability of their function. However, biophotonic molecules are not isolated and the local environment (e.g. solvent, protein shell) can have a large effect on dynamical processes. Nature can use specific intermolecular interactions to alter the energetic and dynamic properties of isolated building blocks thus the efficiency of a particular function can be enhanced with respect to undesired processes.

Our approach towards a molecular level understanding of biophotonic processes is to design time-resolved spectroscopic experiments in a controlled environment to distinguish between intrinsic and environmentally superimposed molecular properties. We use modern femtosecond and picosecond time-resolved pump-probe spectroscopies − both transient absorption and photoelectron photoion coincidence spectroscopy − to investigate dynamic biophotonic processes in the gas-phase, in molecular clusters, where the complexity of the environment can be varied, and in solution. Combined with ab initio calculations outcomes of our research include a molecular level understanding of biophotonic stability and the efficiency of biophotonic processes as well as molecular dynamics criteria for the rational design of novel biophotonic systems.

Recent Publications

G. M. Roberts, C. A. Williams, J. D. Young, A. S. Chatterley, H. Yu, S. Ullrich, V. G. Stavros: Probing Ultrafast Dynamics in Photoexcited Pyrrole: Timescales for 1πσ* Mediated H-atom Elimination, Faraday Discussions 163: Photo-initiated Quantum Molecular Dynamics, 2013, 163, 95.

G. M. Roberts, C. A. Williams, J. D. Young, S. Ullrich, M. J. Paterson, V. G. Stavros: Unraveling Ultrafast Dynamics in Photoexcited Aniline, J. Amer. Chem. Soc., 2012, 134, 12578.

N. L. Evans, H. Yu, G. M. Roberts, V. G. Stavros, S. Ullrich: Observation of Ultrafast NH3 (Ã) State Relaxation Dynamics using a Combination of Time-resolved Photoelectron Spectroscopy and Photoproduct Detection, Phys. Chem. Chem. Phys. 2012., 14, 10401.

H. Yu, N. L. Evans, V. G. Stavros, S. Ullrich: Investigation of Multiple Electronic Excited State Relaxation Pathways Following 200 nm Photolysis of Gas-phase Imidazole, Phys. Chem. Chem. Phys. 2012, 14, 6259.

G. M. Roberts, C. A. Williams, M. J. Paterson, S. Ullrich, V. G. Stavros: Comparing the ultraviolet photostability of azole chromophores, Chemical Sciences 2012, 3, 1192.

C. A. Williams, G. M. Roberts, H. Yu, N. L. Evans, S. Ullrich, V. G. Stavros: Exploring Ultrafast H-Atom Elimination versus Photofragmentation Pathways in Pyrazole Following 200 nm Excitation, J. Phys. Chem. 2012, 116, 2600.

R. Crespo-Otero, M. Barbatti, H. Yu, N. L. Evans, S. Ullrich: The ultrafast dynamics of UV-excited imidazole, ChemPhysChem 2011, 12, 3365.

M. Barbatti, S. Ullrich: Ionization potentials of adenine along the internal conversion pathways, Phys. Chem. Chem. Phys. 2011, 13, 15492.

N. L. Evans, S. Ullrich, C. J. Bennett, R. I. Kaiser: On the Interaction of Adenine with Ionizing Radiation – Mechanistical Studies and Astrobiological Implications, Astrophys. J. 2011, 730, 69.

N. L. Evans, S. Ullrich: Wavelength dependence of electronic relaxation in isolated adenine using UV femtosecond time-resolved photoelectron spectroscopy, J. Phys. Chem. A 2010, 114, 11225.

A. N. Brouillette, N. Evans, W. M. Potter, S. Ullrich: Time-resolved Photoelectron Spectroscopy and the Photoprotective Properties of Adenine, The Journal of Undergraduate Research in Physics, Volume 22, 2009.

C. Z. Bisgaard, H. Satzger, S. Ullrich, A. Stolow: Excited state dynamics of isolated DNA bases: A case study of Adenine, ChemPhysChem 2009, 10, 101. 

A. M. D. Lee, J. D. Coe, S. Ullrich, M.-L. Ho, S.-J. Lee, B.-M. Cheng, M. Z. Zgierski, I-C. Chen, T. J. Martínez, A. Stolow: Substituent effects on Dynamics at Conical Intersections: alpha,beta –enones, J. Phys. Chem. A 2007, 111, 11948.

H. R. Hudock, B. G. Levine, A. L. Thompson, H. Satzger, D. Townsend, N. Gador, S. Ullrich, A. Stolow, T. J. Martínez: Ab Initio Molecular Dynamics and Time-Resolved Photoelectron Spectroscopy of Electronically Excited Uracil and Thymine, J. Phys. Chem. 2007, 111, 8500.

H. Satzger, D. Townsend, M. Z. Zgierski, S. Patchkovskii, S. Ullrich, A. Stolow: Primary processes underlying the photostability of isolated DNA bases: adenine, PNAS 2006, 103, 10196.

E. Samoylova, H. Lippert, S. Ullrich, I.V. Hertel, W. Radloff, T. Schultz: Dynamics of photoinduced processes in adenine and thymine base pairs, J. Amer. Chem. Soc. 2005, 127, 1782.

S. Ullrich, T. Schultz, M.Z. Zgierski, A. Stolow: Electronic relaxation mechanism in DNA and RNA bases studied by time-resolved photoelectron spectroscopy, Phys. Chem. Chem. Phys. 2004, 6, 2796. 

S. Ullrich, T. Schultz, M.Z. Zgierski, A. Stolow: Direct observation of electronic relaxation dynamics in adenine via time-resolved photoelectron spectroscopy, J. Amer. Chem. Soc., Communication 2004, 126, 2262