Forthcoming Events

05.09.2022 - 09.09.2022, Iseolago hotel, Iseo, Italy.


MUST2022 Conference- a great success!
New scientific highlights- by MUST PIs Wörner, Chergui, and Richardson
FELs of Europe prize for Jeremy Rouxel- “Development or innovative use of advanced instrumentation in the field of FELs”
Ruth Signorell wins Doron prizefor pioneering contributions to the field of fundamental aerosol science
New FAST-Fellow Uwe Thumm at ETH- lectures on Topics in Femto- and Attosecond Science
International Day of Women and Girls in Science- SSPh asked female scientists about their experiences
New scientific highlight- by MUST PIs Milne, Standfuss and Schertler
EU XFEL Young Scientist Award for Camila Bacellar,beamline scientist and group leader of the Alvra endstation at SwissFEL
Prizes for Giulia Mancini and Rebeca Gomez CastilloICO/IUPAP Young Scientist Prize in Optics & Ernst Haber 2021
Nobel Prize in Chemistry awarded to RESOLV Member Benjamin List- for the development of asymmetric organocatalysis
NCCR MUST at Scientifica 2021- Lightning, organic solar cells, and virtual molecules
#NCCRWomen- NCCR MUST celebrates 50 years women’s right to vote in Switzerland

X-ray multiphoton ionization and the phase problem in coherent diffractive imaging

Date Di, 24.09.2013 - Di, 24.09.2013
Time 16:45
Speaker Prof. Dr. Robin Santra, Center for Free-Electron Laser Science, Hamburg, Germany
Location ETH Zurich, Hönggerberg Campus, HCI J 3
Program The coherent x-ray scattering pattern of a molecule is connected to the modulus squared of the Fourier transform of the electron density of the molecule. The phase of this Fourier transform is not measured. As a consequence, a reconstruction of the electron density—and thus of the molecular structure—is not immediately possible. In x-ray crystallography at storage-ring-based synchrotron radiation sources, the multi-wavelength anomalous diffraction (MAD) method is used to determine phase information by employing anomalous scattering from heavy atoms. X-ray free-electron lasers (FELs) provide the extremely high x-ray intensity required for revealing the structure of single molecules or nanocrystals, but the phase problem remains largely unsolved. A particular challenge is that, at high x-ray intensity, samples experience severe electronic radiation damage, especially to heavy atoms, which hinders direct implementation of MAD with x-ray FELs. In the first part of the talk, I will discuss how MAD phasing can be extended to high x-ray intensity [1]. The proposed technique relies on the existence of a Karle-Hendrickson-type equation in the high-intensity regime and requires the ability to computationally predict the x-ray-induced ionization dynamics of heavy atoms. In the second part of the talk, this ability will be put to the test. I will review x-ray FEL experiments that have been carried out on atomic xenon and will compare the observations to extensive first-principles calculations [2,3]. At sufficiently high photon energies, there is good agreement between experiment and theory. However, close to inner-shell edges, which play a key role for MAD phasing, specific discrepancies are found. A strategy will be discussed that is expected to allow us to eliminate these discrepancies.

[1] S.-K. Son, H. N. Chapman, and R. Santra, Phys. Rev. Lett. 107, 218102 (2011).
[2] B. Rudek et al., Nature Photonics 6, 858 (2012).
[3] H. Fukuzawa et al., Phys. Rev. Lett. 110, 173005 (2013).

Host: Hans Jakob Wörner, Laboratorium für Physikalische Chemie, LPC
Download (75 KB)
(75 KB)
NCCR MUST Office : ETHZ IQE/ULP-HPT H3 | Auguste-Piccard-Hof 1 | 8093 Zurich | E-Mail
The National Centres of Competence in Research (NCCR) are a research instrument of the Swiss National Science Foundation