Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultrafast laser reveals details about slow electrons

24.06.2003


With the help of ultrafast lasers, Dutch researcher Anouk Wetzels from the FOM Institute for Atomic and Molecular Physics has visualised the wave function of slow electrons. The wave function describes how the electron moves around the nucleus of an atom. With this it is possible to directly visualise atomic and even molecular wave functions.

Wetzels used light pulses with a duration of a millionth of a millionth of a second to visualise the wave function of electrons in atoms. With these rapid pulses the physicist specifically kicked electrons out of an atom. A special technique called velocity map imaging was then used to visualise the speed distribution of the electrons. This resulted in a direct measurement of the wave function of an electron in a Rydberg atom.

In Rydberg atoms the outermost electron is so slow that the orbiting time is longer than the duration of an ultrafast light pulse. As a result of this, the interaction between the pulse, which consists of just half a wavelength, and the electron can be seen as a ’kick’. The result of the kick depends on the location and speed of the electron in its orbit around the nucleus. By kicking the electron in the direction of the detector, the speeds of the electrons perpendicular to the detector remain unchanged.



In velocity map imaging the electrons collide with a fluorescent screen. The collisions here cause points of light. The researchers measure the speeds in the surface of the detector and in this manner obtain two-dimensional data about the wave function of the electron.

Light consists of waves with a given wavelength. But light can also be described as a collection of particles, so-called photons. These photons have a specific energy which is directly related to the wavelength of the light. Therefore all of the photons in a blue light pulse have the same amount of energy. When they interact with a material, photons transfer their energy to the electrons in atoms or molecules.

However this photon theory, based on quantum mechanics, could not be used in Wetzels’ experiments. Instead of using light of one given colour, she used light pulses that contained photons with different energies. The Rydberg electron absorbs several photons simultaneously. The interaction results in a targeted force, or in other words a sudden kick, from the light pulse. This mechanism can be described by the simpler theory of classical mechanics.

Just as light is both a particle and a wave, each particle can also be described as a wave. Therefore electrons are not just negatively-charged particles but also waves with a certain amplitude and wavelength. In quantum mechanics these waves are used to calculate the probability of encountering an electron at a certain time in a certain place.


For further information please contact Anouk Wetzels (AMOLF Institute for Atomic and Molecular Physics). The doctoral thesis will be defended on 1 July 2003. Ms Wetzels supervisor is Prof. W.J. van der Zande, tel. 31-24-365-2025, e-mail: zande@sci.kun.nl.

The research was funded by the Netherlands Organisation for Scientific Research.

Nalinie Moerlie | EurekAlert!
Further information:
http://www.nwo.nl

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>