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CPP: Chemische Physik und Polymerphysik

CPP 21: POSTER B

CPP 21.11: Poster

Tuesday, March 25, 2003, 19:00–21:00, ZEU/250

Ultrafast mid-infrared photon echo measurements on hydrogen bonded acetic acid dimers — •Nils Huse, Karsten Heyne, Erik T. J. Nibbering, and Thomas Elsaesser — Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2 A, 12489 Berlin

Femtosecond photon echo spectroscopy gives insight into the mechanisms which determine the lineshape of O-H stretching bands in hydrogen bonds. As a model system, we investigated O-H stretching excitations of coupled hydrogen bonds in cyclic acetic acid dimers. In the 2-pulse photon echo, one finds a fast, sub-100 fs decay of the macroscopic coherent polarization, followed by weak recurrences. This behavior gives evidence of a multi-level coherence originating from the anharmonic coupling of the fast O-H stretching motion to low-frequency modes of the dimers. From the photon echo data and comparative hole-burning measurements with femtosecond infrared pulses, a dephasing time of the O-H stretching transition of 200 fs is derived. 3-pulse photon echo peak shift data suggest a predominant homogeneous broadening of the O-H stretching band.