Reaction microscope 'X-rays' individual molecules

Date:
June 11, 2020
Source:
Goethe University Frankfurt
Summary:
For more than 200 years, we have been using X-rays to look inside
matter, and progressing to ever smaller structures -from crystals
to nanoparticles. Now, physicists have achieved a qualitative
leap forward: using a new experimental technique, they have been
able to 'X-ray' molecules such as oxygen and view their motion in
the microcosm.



FULL STORY ==========================================================================
"The smaller the particle, the bigger the hammer." This rule from
particle physics, which looks inside the interior of atomic nuclei
using gigantic accelerators, also applies to this research. In order to
"X-ray" a two-atom molecule such as oxygen, an extremely powerful and ultra-short X-ray pulse is required. This was provided by the European
XFEL which started operations in 2017 and is one of the the strongest
X-ray source in the world

==========================================================================
In order to expose individual molecules, a new X-ray technique is also
needed: with the aid of the extremely powerful laser pulse the molecule is quickly robbed of two firmly bound electrons. This leads to the creation
of two positively charged ions that fly apart from each other abruptly
due to the electrical repulsion. Simultaneously, the fact that electrons
also behave like waves is used to advantage. "You can think of it like a sonar," explains project manager Professor Till Jahnke from the Institute
for Nuclear Physics.

"The electron wave is scattered by the molecular structure during
the explosion, and we recorded the resulting diffraction pattern. We
were therefore able to essentially X-ray the molecule from within, and
observe it in several steps during its break-up." For this technique,
known as "electron diffraction imaging," physicists at the Institute
for Nuclear Physics spent several years further developing the COLTRIMS technique, which was conceived there (and is often referred to as a
"reaction microscope"). Under the supervision of Dr Markus Scho"ffler, a corresponding apparatus was modified for the requirements of the European
XFEL in advance, and designed and realised in the course of a doctoral
thesis by Gregor Kastirke. No simple task, as Till Jahnke observes: "If
I had to design a spaceship in order to safely fly to the moon and back,
I would definitely want Gregor in my team. I am very impressed by what
he accomplished here." The result, which was published in the current
issue of the journal Physical Review X, provides the first evidence that
this experimental method works. In the future, photochemical reactions of individual molecules can be studied using these images with their high
temporal resolution. For example, it should be possible to observe the
reaction of a medium-sized molecule to UV rays in real time. In addition,
these are the first measurement results to be published since the start
of operations of the Small Quantum Systems (SQS) experiment station at
the European XFEL at the end of 2018.


========================================================================== Story Source: Materials provided by Goethe_University_Frankfurt. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Gregor Kastirke, Markus S. Scho"ffler, Miriam Weller, Jonas Rist,
Rebecca
Boll, Nils Anders, Thomas M. Baumann, Sebastian Eckart, Benjamin
Erk, Alberto De Fanis, Kilian Fehre, Averell Gatton, Sven Grundmann,
Patrik Grychtol, Alexander Hartung, Max Hofmann, Markus Ilchen,
Christian Janke, Max Kircher, Maksim Kunitski, Xiang Li, Tommaso
Mazza, Niklas Melzer, Jacobo Montano, Valerija Music, Giammarco
Nalin, Yevheniy Ovcharenko, Andreas Pier, Nils Rennhack, Daniel
E. Rivas, Reinhard Do"rner, Daniel Rolles, Artem Rudenko, Philipp
Schmidt, Juliane Siebert, Nico Strenger, Daniel Trabert, Isabel
Vela-Perez, Rene Wagner, Thorsten Weber, Joshua B.

Williams, Pawel Ziolkowski, Lothar Ph. H. Schmidt, Achim Czasch,
Florian Trinter, Michael Meyer, Kiyoshi Ueda, Philipp V. Demekhin,
Till Jahnke.

Photoelectron Diffraction Imaging of a Molecular Breakup Using an
X-Ray Free-Electron Laser. Physical Review X, 2020; 10 (2) DOI:
10.1103/ PhysRevX.10.021052 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200611094204.htm

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