Abstract of:
T. Hasche, T. W. Canzler, R. Scholz, M. Hoffmann, K. Schmidt,
Th. Frauenheim, and K. Leo,
Coherent External and Internal Phonons in Quasi-One-Dimensional Organic
Molecular Crystals,
Phys. Rev. Lett. 86 (2001) 4060-4063.
Abstract:
We have directly time resolved coherent phonon oscillations in
quasi-one-dimensional organic crystals of MePTCDI
(N-N'-dimethylperylene-3,4,9,10-dicarboximide), using femtosecond pump-probe
experiments. We observe both higher-energy oscillations caused by
intramolecular vibrations (internal phonons) and, for the first time in a
quasi-one-dimensional organic system, lower-energy modulations which are
related to coherent lattice phonons (external phonons). For internal Ag
vibrations, the coherence decay time of about 2 ps is almost independent of
the mode. In contrast, the damping time of the external phonons increases
strongly with decreasing energy.
homepage M. Hoffmann
last updated: Dec 2007