Dresden 2011 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 9: Femtosecond Spectroscopy II

MO 9.9: Vortrag

Dienstag, 15. März 2011, 12:45–13:00, TOE 317

Fs time-resolved photoelectron spectroscopy of solvated electrons — •Franziska Buchner, Andrea Lübcke, Thomas Schultz, and Ingolf-Volker Hertel — Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin

Solvated electrons are potent reagents and have been studied for decades. However, they still ask us riddles.

We combined fs time-resolved photoelectron spectroscopy with a liquid jet of aqueous sodium iodide solution to study energetics and dynamics of solvated electrons. These are generated by ultrafast photodetachment from iodide anions with a 6.20 eV laser pulse. The temporal evolution of these solvated electrons are probed by a delayed 4.65 eV laser pulse. At early delay times, we find two distinct populations of solvated electrons: those that are instantaneously strongly bound ("cold") and a fraction of initially weakly bound ("hot") electrons. We observe thermalization of the "hot" electrons which transform into "cold" electrons on the timescale of about 1 ps and geminate recombination with the iodide radical.

We will further present and discuss concentration-dependent photoelectron spectra and the influence of the counter ion on energetics and dynamics of the species involved. Our results point towards a high surface sensitivity and we will draw conclusions on the existence of surface-bound solvated electrons in aqueous solutions.