Researchers present concept for a new technique to study superheavy
elements
Merging methodologies from physics and chemistry for the optical
spectroscopy of superheavy elements

Date:
July 13, 2020
Source:
Johannes Gutenberg Universitaet Mainz
Summary:
Merging methodologies from physics and chemistry for the optical
spectroscopy of superheavy elements.



FULL STORY ========================================================================== Superheavy elements are intriguing nuclear and atomic quantum systems that challenge experimental probing as they do not occur in nature and, when synthesized, vanish within seconds. Pushing the forefront atomic physics research to these elements requires breakthrough developments towards fast atomic spectroscopy techniques with extreme sensitivity. A joint effort
within the European Union's Horizon 2020 Research and Innovation program
and led by Dr. Mustapha Laatiaoui from Johannes Gutenberg University Mainz (JGU) culminated in an optical spectroscopy proposal: The so-called Laser Resonance Chromatography (LRC) should enable such investigations even at
minute production quantities. The proposal has recently been published
in two articles in Physical Review Letters and Physical Review A.


========================================================================== Superheavy elements (SHEs) are found at the bottom part of the periodic
table of elements. They represent a fertile ground for the development
of understanding on how such exotic atoms can exist and work when
an overwhelming number of electrons in atomic shells and protons and
neutrons in the nucleus come together. Insights into their electronic
structure can be obtained from optical spectroscopy experiments unveiling element-specific emission spectra.

These spectra are powerful benchmarks for modern atomic-model calculations
and could be useful, for example, when it comes to searching for traces
of even heavier elements, which might be created in neutron-star merger
events.

LRC approach combines different methods Although SHEs have been
discovered decades ago, their investigation by optical spectroscopy
tools lack far behind the synthesis. This is because they are produced
at extremely low rates at which traditional methods simply do not
work. So far, optical spectroscopy ends at nobelium, element 102 in
the periodic table. "Current techniques are at the limit of what is
feasible," explained Laatiaoui. From the next heavier element on,
the physicochemical properties change abruptly and impede providing
samples in suitable atomic states." Together with research colleagues,
the physicist has therefore developed the new LRC approach in optical spectroscopy. This combines element selectivity and spectral precision
of laser spectroscopy with ion-mobility mass spectrometry and merges
the benefits of a high sensitivity with the "simplicity" of optical
probing as in laser-induced fluorescence spectroscopy. Its key idea is
to detect the products of resonant optical excitations not on the basis
of fluorescent light as usual, but based on their characteristic drift
time to a particle detector.

In their theoretical work, the researchers focused on singly charged lawrencium, element 103, and on its lighter chemical homolog. But the
concept offers unparalleled access to laser spectroscopy of many other monoatomic ions across the periodic table, in particular of the transition metals including the high-temperature refractory metals and elements
beyond lawrencium. Other ionic species like triply-charged thorium
shall be within reach of the LRC approach as well. Moreover, the method
enables to optimize signal-to-noise ratios and thus to ease ion mobility spectrometry, state-selected ion chemistry, and other applications.

Dr. Mustapha Laatiaoui came to Johannes Gutenberg University Mainz and
the Helmholtz Institute Mainz (HIM) in February 2018. In late 2018, he
received an ERC Consolidator Grant from the European Research Council
(ERC), one of the European Union's most valuable funding grants, for
his research into the heaviest elements using laser spectroscopy and
ion mobility spectroscopy. The current publications also included work
that Laatiaoui had previously carried out at GSI Helmholtzzentrum fu"r Schwerionenforschung in Darmstadt and at KU Leuven in Belgium.

This work was conducted in cooperation with Alexei A. Buchachenko from the Skolkovo Institute of Science and Technology and the Institute of Problems
of Chemical Physics, both in Moscow, Russia, and Larry A. Viehland from
Chatham University, Pittsburgh, USA.


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


========================================================================== Journal References:
1. Mustapha Laatiaoui, Alexei A. Buchachenko, Larry A. Viehland. Laser
Resonance Chromatography of Superheavy Elements. Physical Review
Letters, 2020; 125 (2) DOI: 10.1103/PhysRevLett.125.023002
2. Mustapha Laatiaoui, Alexei A. Buchachenko, Larry
A. Viehland. Exploiting
transport properties for the detection of optical pumping in
heavy ions.

Physical Review A, 2020; 102 (1) DOI: 10.1103/PhysRevA.102.013106 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200713125519.htm

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