ausblenden:
Schlagwörter:
charge-carrier injection;electron transfer;femtochemistry;photoelectron spectroscopy;time-resolved spectroscopy
Zusammenfassung:
The general case of a heterogeneous electron-transfer reaction
is realized by ultrafast electron transfer from a light-absorbing
molecule to a wide continuum of electronic acceptor states, realizing
the so-called wide band limit. Experimental data obtained
for perylene dye/TiO2 systems confirm the predictions
of fully quantum mechanical model calculations of the dynamics.
The energy distribution of the injected electron shows an
energy loss due to excitations of high-energy (quantum) vibrational
modes in the ionized perylene moiety. The electrontransfer
mechanism is non-adiabatic and the reaction is ultrafast,
for example, with a time constant of 9 fs for the COOH
anchor-bridge group. The underlying strong coupling of the
electronic states to high-energy vibrational modes is a characteristic
feature of sensitizer molecules.
