CFEL Workshop on Nanoscale Imaging of Materials

Jim Zuo (Dept. of Materials Science and Engineering, University of Illinois)

Electrons for Imaging Molecular Motions and Atomic Reactions, the Scientific Opportunity and

Structure determination of individual molecules so far has not been possible, because the dose
required for recording atomic resolution diffraction data often leads to extensive structure damage
before the molecular diffraction pattern can be recorded. X-ray diffraction “snapshot” technique has
been developed using femtoseconds (fs) pulses from a hard X-ray free electron laser to overcome
this limit. For electrons, because of their large scattering cross section, the same diffraction power can
be achieved with ~106 electrons. This talk will explore the limits of electron molecular diffraction, and
scientific opportunity of using electrons for imaging molecular motions and atomic reactions with new
developments in electron microscopy, pulsed electron sources and electron detectors.
Tim Salditt (Institut für Röntgenphysik, Universität Göttingen)
X-ray nano-imaging of biomolecularmatter: a matter of contrast and a matter of resolution
Images of molecular functions in complex environments require a combination of high spatial
resolution, quantitative contrast, and full compatibility with environmental conditions. Circumventing
the fabrication constraints of zone plate, novel lens-less x-ray imaging techniques approaches have
emerged, where the object function is reconstructed from the measured intensities without the need
of an object lens. We present recent results on coherent x-ray tomography of bio-molecular samples
and biological cells.

Ian Robinson (University College London)

Structural principles for nanoparticles: time-domain investigations

Recent experiments at the XPP station of LCLS showed unexpectedly abrupt early time heating
behavior of single gold nanocrystals. This is explained, with the help of MD simulations, to be due to
an electronic heating effect. Subsequent time evolution is consistent with acoustic “ringing” of the
normal modes.

Henry Chapman (DESY-CFEL Hamburg)

Femtosecond Nanocrystallography with X-ray Free-Electron Lasers

X-ray pulses from free-electron lasers are of high enough intensity and of sufficiently short duration
that single-shot diffraction patterns can be obtained from a sample before significant damage
occurs. We have shown that this idea of "diffraction before destruction" holds to atomic resolution,
and are applying it to solve the structures of proteins from samples too small or radiation sensitive for
conventional measurements.