Hannover 2016 – scientific programme
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MO: Fachverband Molekülphysik
MO 15: Femtosecond Spectroscopy 3
MO 15.6: Talk
Thursday, March 3, 2016, 12:30–12:45, f102
Femtosecond oxygen K-edge absorption spectroscopy of thymine — T. J. A. Wolf1, R. Heilemann Myhre1,2, H. Koch1,2, A. Battistoni1, N. Berrah3, P. H. Bucksbaum1, R. Coffee4, S. Coriani5, G. Coslovic4, J. Cryan1, R. Feifel6, K. Gaffney1, J. Grilj7, T. Martinez1,8, S. Miyabe1, S. Möller4, M. Mucke9, A. Natan1, R. Obaid3, T. Osipov4, O. Plekan10, A. Sage3, R. Squibb6, S. Wang1, and •M. Gühr1,11 — 1PULSE, SLAC National Accelerator Laboratory and Stanford University, USA — 2Chemistry Dept., NTNU, Trondheim, Norway — 3Physics Dept., University of Connecticut, Storrs USA — 4LCLS, SLAC National Accelerator Laboratory, USA — 5Chemistry Dept., Universita' di Trieste, Italy — 6Physics Dept., Gotheborg University,Sweden — 7LSU, EPFL, Lausanne, Switzerland — 8Chemistry Dept., Stanford University, USA — 9Physics Dept., Uppsala University, Sweden — 10Syncrotrone Elettra, Trieste, Italy — 11Physics and Astronomy, Universität Potsdam, Germany
We show first results of ultrafast soft x-ray absorption spectroscopy in the gas phase. After ultraviolet excitation to the ππ* state, the nucleobase thymine undergoes internal conversion to the nπ* and electronic ground state. We probe this nonadiabatic process using resonant absorption at the oxygen K-edge. We identify a UV induced bleach of the initially unoccupied π* states around 531 eV in the absorption spectrum. In addition, we observe an entirely UV generated absorption feature about 4.5 eV lower than the π* resonances, which we assign to a molecular nonadiabatic relaxation channel.