Forthcoming Events

29.01.2020 - 31.01.2020, ETH Hönggerberg, Zürich
29.01.2020 - 31.01.2020, DESY-Hamburg and European XFEL, Schenefeld, Germany
01.02.2020 - 02.02.2020, Renaissance Tuscany Il Ciocco, Lucca, Italy


Ruth Signorell receives the Humboldt Prize- awarded in recognition of outstanding achievements in research and teaching
New scientific highlights- by MUST PIs Keller, Chergui, Richardson / Vanicek, Wörner, Castiglioni / Osterwalder / Hengsberger / van Bokhoven
Ursula Keller wins the SPIE 2020 Gold Medal- awarded in recognition of outstanding engineering or scientific accomplishments
Nobel Prize winner Gerard Mourou - Physics Colloquium 11.12.19: Passion Extreme Light
Paths to a professorship – 23 interviews
New scientific highlights- by MUST PIs Peter Hamm, Ursula Keller, Jörg Standfuss, and Fabrizio Carbone

Peter Hamm and co-workers: time-resolved terahertz spectroscopy captures the early stages of the photodetached electron and furthermore provides a direct measure of its initial size

July 6, 2014

Direct Observation of the Collapse of the Delocalized Excess Electron in Water

It is generally assumed that the hydrated electron occupies a quasi-spherical cavity surrounded by only a few water molecules in its equilibrated state. However, in the very moment of its generation, before water has had time to respond to the extra charge, it is expected to be significantly larger in size. According to a particle-in-a-box picture, the frequency of its absorption spectrum is a sensitive measure of the initial size of the electronic wavefunction. Here, using transient terahertz spectroscopy, we show that the excess electron initially absorbs in the far-infrared at a frequency for which accompanying ab initio molecular dynamics simulations estimate an initial delocalization length of ≈40 Å. The electron subsequently shrinks due to solvation and thereby leaves the terahertz observation window very quickly, within ≈200 fs.

Publication: J. Savolainen, F. Uhlig, S. Ahmed, P. Hamm and P. Jungwirth (2014) Direct Observation of the Collapse of the Delocalized Excess Electron in Water, Nature Chem 6, 697-701 (10.1038/nchem.1995)

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