Berlin 2001 – wissenschaftliches Programm
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MO: Molekülphysik
MO 8: Posters Thursday: Dissociation and other Collision Processes
MO 8.6: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Fs-dynamics in the fragment-cage interaction: I2 in Kr — •Markus Gühr, Matias Bargheer, Peter Dietrich, and Nikolaus Schwentner — Institute of Experimental Physics, FU-Berlin, Arnimallee 14, 14195 Berlin
We present an expanded scheme which allows to derive potential energy surfaces together with energy dissipation rates and information on the dynamics in the solid phase from femtosecond pump-probe spectroscopy.
From systematic variations of pump and probe energies we extract essential features of the interaction of the molecular fragment with the cage atoms. The center-of-mass motion of the I2 vibrational wavepacket in the B-state is followed by tuning the probe-photon energy and thus the spatial position of the probe window. From such a trajectory starting with energies near the gas phase dissociation limit we can directly obtain the region where fragment-cage interaction becomes strong. The change of velocity indicates a dramatic energy loss and scattering to the bound part of the molecular potential. The returning of the fragment is further hindered by matrix-atoms entering the belt region of the elongated I 2.
Probing on predissociated surfaces yields information on nonadiabatic transitions and dynamics. Temperature variation provides insight in the symmetry properties of the curve-crossing matrix elements.