Nav: Home

Electrons in rapid motion

February 14, 2020

A team headed by Prof. Dr. Frank Stienkemeier and Dr. Lukas Bruder from the Institute of Physics at the University of Freiburg has succeeded in observing in real-time ultrafast quantum interferences -- in other words the oscillation patterns -- of electrons which are found in the atomic shells of rare gas atoms. They managed to observe oscillations with a period of about 150 attoseconds -- an attosecond is a billionth of a billionth of a second. To this end, the scientists excited rare gas atoms with specially prepared laser pulses. Then they tracked the response of the atoms with a new measurement technique that enabled them to study quantum mechanical effects in atoms and molecules at extremely high time resolution. The researchers present their results in the latest edition of Nature Communications.

Numerous chemical reactions, such as the breaking of bonds in molecules, are triggered by the absorption of light. In the first instant after the absorption, the distribution of the electrons in the atomic shell changes, significantly influencing the subsequent course of the reaction. This alteration happens extremely quickly; the timescales reach into the attosecond range. Previously-used spectroscopic technologies, which use visible laser pulses, are not fast enough to track such processes. So researchers around the world are currently developing innovative laser sources and adequate spectroscopic technologies in the ultra-violet and X-ray ranges.

Stienkemeier's team has extended a technology known from the visible spectrum range, coherent pump-probe spectroscopy, into the ultra-violet range. This is the spectral range between X-ray radiation and ultra-violet light. To do this, the scientists prepared a sequence of two ultra-short laser pulses in the extreme ultra-violet range at the FERMI free electron laser in Trieste, Italy. The pulses were separated by a precisely-defined time interval and had a precisely-defined phase relationship to one another. The first pulse starts the process in the electron shell (pump-process). The second pulse probes the status of the electron shell at a later point (probe-process). By altering the time interval and the phase relationship, the researchers could reach conclusions on the temporal development in the electron shell. "The greatest challenge was to achieve precise control over the pulse properties and to isolate the weak signals," explains Andreas Wituschek, who was in charge of the experimental procedure.

The Freiburg physicists studied the rare gas argon, amongst others. In argon the pump-pulse causes a special configuration of two electrons within the atomic shell: this configuration disintegrates, with one electron leaving the atom in a very short time and the atom finally remaining behind as an ion. The researchers succeeded for the first time in observing the immediate temporal decay of the quantum interference, as one electron left the atom. "This experiment paves the way for many new applications in the study of atomic and molecular processes after selective stimulation with high-energy radiation in the extreme ultra-violet range," says Bruder.
-end-
The research project was funded within the framework of the International Graduate School CoCo, which was established by the German Research Foundation (DFG), as well as by the COCONIS project of the European Research Council (ERC) and LoKoFEL project of the Federal Ministry of Education and Research (BMBF).

Original publication:

Wituschek A., Bruder L., Allaria E., Bangert U., Binz M., Borghes R., Callegari C., Cerullo G., Cinquegrana P., Giannessi L., Danailov M., Demidovich A., Di Fraia M., Drabbels M., Feifel R., Laarmann T., Michiels R., Mirian N.S., Mudrich M., Nikolov I., O'Shea FH., Penco G., Piseri P., Plekan O., Prince K.C., Przystawik A., Ribič P.R., Sansone G., Sigalotti P., Spampinati S., Spezzani C., Squibb R.J., Stranges S., Uhl D. & Stienkemeier F. (2020):Tracking attosecond electronic coherences using phase-manipulated extreme ultraviolet pulses. In: Nature Communications 11, 883 (2020). DOI: 10.1038/s41467-020-14721-2

Contact:

Institute of Physics
University of Freiburg

University of Freiburg

Related Electrons Articles:

Plasma electrons can be used to produce metallic films
Computers, mobile phones and all other electronic devices contain thousands of transistors, linked together by thin films of metal.
Flatter graphene, faster electrons
Scientists from the Swiss Nanoscience Institute and the Department of Physics at the University of Basel developed a technique to flatten corrugations in graphene layers.
Researchers develop one-way street for electrons
The work has shown that these electron ratchets create geometric diodes that operate at room temperature and may unlock unprecedented abilities in the illusive terahertz regime.
Photons and electrons one on one
The dynamics of electrons changes ever so slightly on each interaction with a photon.
Using light to put a twist on electrons
Method with polarized light can create and measure nonsymmetrical states in a layered material.
What if we could teach photons to behave like electrons?
The researchers tricked photons - which are intrinsically non-magnetic - into behaving like charged electrons.
Electrons in rapid motion
Researchers observe quantum interferences in real-time using a new extreme ultra-violet light spectroscopy technique.
Taming electrons with bacteria parts
In a new study, scientists at the MSU-DOE Plant Research Laboratory report a new synthetic system that could guide electron transfer over long distances.
Hot electrons harvested without tricks
Semiconductors convert energy from photons into an electron current. However, some photons carry too much energy for the material to absorb.
Cooling nanotube resonators with electrons
In a study in Nature Physics, ICFO researchers report on a technique that uses electron transport to cool a nanomechanical resonator near the quantum regime.
More Electrons News and Electrons Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Processing The Pandemic
Between the pandemic and America's reckoning with racism and police brutality, many of us are anxious, angry, and depressed. This hour, TED Fellow and writer Laurel Braitman helps us process it all.
Now Playing: Science for the People

#568 Poker Face Psychology
Anyone who's seen pop culture depictions of poker might think statistics and math is the only way to get ahead. But no, there's psychology too. Author Maria Konnikova took her Ph.D. in psychology to the poker table, and turned out to be good. So good, she went pro in poker, and learned all about her own biases on the way. We're talking about her new book "The Biggest Bluff: How I Learned to Pay Attention, Master Myself, and Win".
Now Playing: Radiolab

Invisible Allies
As scientists have been scrambling to find new and better ways to treat covid-19, they've come across some unexpected allies. Invisible and primordial, these protectors have been with us all along. And they just might help us to better weather this viral storm. To kick things off, we travel through time from a homeless shelter to a military hospital, pondering the pandemic-fighting power of the sun. And then, we dive deep into the periodic table to look at how a simple element might actually be a microbe's biggest foe. This episode was reported by Simon Adler and Molly Webster, and produced by Annie McEwen and Pat Walters. Support Radiolab today at Radiolab.org/donate.