An international research team led by Markus Gühr’s group at the University of Potsdam performed laser experiments at Deutsches Elektronen-Synchrotron DESY to monitor charge motions in light-excited molecules of thiouracil, which is a modified nucleobase. This class of molecules has a variety of medical applications, including possible novel cancer therapies. Their basic research now published in Nature Communications opens up the possibility to map the charge flowing inside the molecular landscape.

More Information from University of Potsdam

DESY NEWS

PRO PHYSIK

CUI Hamburg

A feature on the work in our group by the University of Potsdam – in German.

DPG – PRO PHYSIK wrote about our work:

Molekülschwingungen im Daumenkino

• 06. October 2016

Zwei Forschergruppen gelingt die Aufnahme molekularer Schwingungen mit Röntgen- und Elektronenpulsen.

Nicht nur Chemiker träumen davon, Schwingungen und Reaktionen von Molekülen wie in einem Film aufzunehmen. Auch für viele biologische Prozesse – insbesondere für photo­induzierte Reaktionen – würde dies ein ganz neues Verständnis ermöglichen. Zwar gibt es bereits einige Methoden, die solche Filme liefern können. Sie basieren jedoch meist auf indirekten Messungen des Zustandes, etwa aus Bestimmungen des Absorptions­spektrums. Will man aus solchen „femto­chemischen” Messungen die Dynamik des Moleküls berechnen, so benötigt man ein gutes Vorver­ständnis der Potenzial­oberfläche der elek­tronischen Zustände in Abhängigkeit von der Form des Moleküls, was natürlich die Zahl der zu unter­suchenden molekularen Reaktionen begrenzt…

 

continue reading on

http://www.pro-physik.de/details/news/9927491/Molekuelschwingungen_im_Daumenkino.html

Marc Vrakking wrote a Viewpoint for our latest publication on diffraction from molecular wavepakets:

 

“The scientist Ahmed Zewail (1946–2016) was awarded the Nobel Prize in Chemistry in 1999 for his contributions to femtochemistry, the field that studies chemical changes on the time scales on which atoms move—femtoseconds (fs). Femtochemistry experiments follow the electronic or structural dynamics of a molecule by first exciting it with a femtosecond “pump” laser pulse, and then observing it using a delayed “probe” pulse [1]. Most femtochemistry experiments, however, probe molecules through indirect observables: They rely on the fact that the chemical dynamics are accompanied by changes in the molecule’s absorption spectrum. Two independent groups now use more direct approaches to the visualization of atomic motions, recording molecular “movies” by time-resolved x-ray diffraction [2] and time-resolved electron diffraction [3], respectively. Both experiments image, in real time, the changes of the distance separating the two atoms in a vibrating iodine ( I2) molecule. The results represent important progress in our ability to record ultrafast molecular movies with increasing spatial and temporal resolution without relying on complex models.”

… continue reading on:

http://physics.aps.org/articles/v9/112

Joint team from SLAC Accelerator Lab, University of Nebraska and Universität Potsdam takes the ‘Molecular Movies of Vibrating Molecules by Ultrafast Electron Diffraction’

See Press release published on SLAC website

Publication accepted in PRL.

ArXiv paper:

Diffractive Imaging of Coherent Nuclear Motion in Isolated Molecules
J. Yang, M. Guehr, X. Shen, R. Li, T. Vecchione, R. Coffee, J. Corbett, A. Fry, N. Hartmann, C. Hast, K. Hegazy, K. Jobe, I. Makasyuk, J. Robinson, M. S. Robinson, S. Vetter, S. Weathersby, C. Yoneda, X. Wang, M. Centurion
Phys. Rev. Lett. accepted (2016)
arXiv

Für das diesjährige Leibniz-Kolleg haben wir Majed Chergui von der EPFL Lausanne gewinnen können. Er ist bekannt geworden durch eine Vielzahl von ultraschnellen UV und Röntgenspektroskopischen Untersuchungen an chemischen und biologischen Systemen. Prof. Chergui hat zugesagt, den Hauptvortrag am Donnerstag, dem 12. Mai 2016, um 16:00 Uhr am im Haus 27 Raum 0.01 Standort Golm der Universität Potsdam zu halten.

LKP_Poster_1304

Joint team from SLAC Accelerator Lab, University of Nebraska and Universität Potsdam takes the ‘World’s Fastest Electron Diffraction Snapshots of Atomic Motions in Gases’

See Press release published on SLAC website: https://www6.slac.stanford.edu/news/2016-04-05-worlds-fastest-electron-diffraction-snapshots-atomic-motions-gases.aspx

Publication:

Yang, Guehr, Vecchione et al. , Diffractive imaging of a rotational wavepacket in nitrogen molecules with femtosecond megaelectronvolt electron pulses
Nature Communications 7, 11232 (2016)
link to paper

The Volkswagen Foundation supports our group with a 1.3 Mio. Euro Lichtenberg Professorship on “Extreme ultraviolet probing of energy-conversion in photoexcited states”.

Press:

Press release by the Volkswagen foundation

Press release by Potsdam University

Potsdamer Neueste Nachrichten

 

 

 

 

 

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