Hannover 2016 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 17: Electronic Spectroscopy 2

MO 17.3: Vortrag

Donnerstag, 3. März 2016, 15:00–15:15, f102

Multimodal Time-Resolved Spectroscopy of Vibrational Coherence and Population Dynamics in the Excited State — •Takeshi Miki, Marcus Motzkus, and Tiago Buckup — Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany

The interpretation of dynamics in the excited states of molecules often challenges time-resolved spectroscopy in particular due to spectrally overlapping contributions as well as ultrafast optical signals. Multimodal Time-Resolved Spectroscopy combines multiple time-resolved signals to disentangle and map complex molecular dynamics. In this work we exploit two different time-resolved spectroscopies, transient absorption (TA) spectroscopy and pump-degenerate four wave mixing (pump-DFWM) spectroscopy, to map the interplay between population and vibrational coherence dynamics. An algorithm is developed to globally fit the whole spectrally resolved data of both methods. A kinetic model is developed via global target analysis of the TA data, which is further refined by exploiting the very sensitive homodyne signal of pump-DFWM spectroscopy. This way, time decay constants of electronic states, frequency and phase of vibrational molecular modes, and transition dipole moments of excited state transitions can be obtained under the assumption of an unified molecular model. This is applied (i) to disentangle the vibrationally modulated from the not vibrationally modulated stimulated emission and (ii) to determine specific vibrational frequencies and their origin during the deactivation of electronic states. The method is applied to prototype organic molecules.