Emergence of solvated dielectrons observed for the first time

Date:
May 26, 2023
Source:
University of Freiburg
Summary:
Scientists generate low-energy electrons using ultraviolet light.


Facebook Twitter Pinterest LinkedIN Email

==========================================================================
FULL STORY ========================================================================== Solvated dielectrons are the subject of many hypotheses among scientists,
but have never been directly observed. They are described as a pair
of electrons that is dissolved in liquids such as water or liquid
ammonia. To make space for the electrons a cavity forms in the liquid,
which the two electrons occupy. An international research team around
Dr. Sebastian Hartweg, initially at Synchrotron SOLEIL (France), now at
the Institute of Physics at the University of Freiburg and Prof. Dr. Ruth Signorell from ETH Zurich, including scientists from the synchrotron
SOLEIL and Auburn University (US) has now succeeded in discovering a
formation and decay process of the solvated dielectron. In experiments
at the synchrotron SOLEIL (DESIRS beamline), the consortium found direct evidence supported by quantum chemical calculations for the formation
of these electron pairs by excitation with ultraviolet light in tiny
ammonia droplets containing a single sodium atom. The results were
recently published in the scientific journal Science.

Traces of an unusual process When dielectrons are formed by excitation
with ultraviolet light in tiny ammonia droplets containing a sodium atom,
they leave traces in an unusual process that scientists have now been able
to observe for the first time. In this process, one of the two electrons migrates to the neighbouring solvent molecules, while at the same time
the other electron is ejected. "The surprising thing about this is that
similar processes have previously been observed mainly at much higher excitation energies," says Hartweg. The team focused on this second
electron because there could be interesting applications for it. On the
one hand, the ejected electron is produced with very low kinetic energy,
so it moves very slowly. On the other hand, this energy can be controlled
by the irradiated UV light, which starts the whole process. Solvated dielectrons could thus serve as a good source of low-energy electrons.

Generated specifically with variable energy Such slow electrons can
set a wide variety of chemical processes in motion. For example, they
play a role in the cascade of processes that lead to radiation damage in biological tissue. They are also important in synthetic chemistry, where
they serve as effective reducing agents. By being able to selectively
generate slow electrons with variable energy, the mechanisms of such
chemical processes can be studied in more detail in the future. In
addition, the energy made available to the electrons in a controlled
manner might also be used to increase the effectiveness of reduction
reactions. "These are interesting prospects for possible applications
in the future," says Hartweg. "Our work provides the basis for this and
helps to understand these exotic and still enigmatic solvated dielectrons
a little better."
* RELATED_TOPICS
o Matter_&_Energy
# Inorganic_Chemistry # Physics # Chemistry # Spintronics
o Computers_&_Math
# Spintronics_Research
* RELATED_TERMS
o Photoelectric_effect o Ozone o Electroluminescence o
Ultraviolet o Optics o Combustion o Solar_cell o Atom

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


========================================================================== Journal Reference:
1. Sebastian Hartweg, Jonathan Barnes, Bruce L. Yoder, Gustavo
A. Garcia,
Laurent Nahon, Evangelos Miliordos, Ruth Signorell. Solvated
dielectrons from optical excitation: An effective source of
low-energy electrons.

Science, 2023; DOI: 10.1126/science.adh0184 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/05/230526142242.htm

--- up 1 year, 12 weeks, 4 days, 10 hours, 50 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)