Fusion methodologies from physics and chemistry to optical spectroscopy of superheavy elements.
The elements of superheavy are intriguing nuclear and atomic quantum systems that challenge experimental examination as they do not occur in nature and, when synthesized, disappear within seconds. Pushing atomic physics research to the forefront of these elements requires new developments toward fast atomic spectroscopy techniques with extreme sensitivity. A joint effort in the European Union̵7;s Horizon 2020 Research and Innovation program led by Dr Mustapha Laatiaoui from Johannes Gutenberg Mainz University (JGU) has led to a proposal for optical spectroscopy: The so-called Laser Resonance Chromatography (LRC) should allow such investigations even in production quantities per minute. The proposal was recently published in two articles Physical Review Letters u Physical Review A.
Superheavy elements (SHE) are located at the bottom of the periodic table of elements. They represent a breeding ground for developing an understanding of how such exotic atoms can exist and work when a large number of electrons in the atomic shells and protons and neutrons in the nucleus join together. Interests in their electronic structure can be derived from optical spectroscopy experiments that broadcast element-specific emission spectra. These spectra are strong benchmarks for modern calculations of atomic models and can be useful, for example when it comes to searching for traces of even heavier elements, which can arise in neutron fusion events. .
The LRC approach combines different methods
Although SHEs were discovered decades ago, their investigation using an optical spectroscopy tool is far behind in synthesis. This is because they are produced at extremely low rates in which traditional methods simply do not work. So far, optical spectroscopy ends in the nobelium, element 102 in the periodic table. “Current techniques are at the limit of what is feasible,” Laatiaoui explained. From the next heavier element, the physicochemical properties change abruptly and hinder the sampling at suitable atomic states. “
Together with research colleagues, the physicist developed the new LRC approach in optical spectroscopy. This combines the element selectivity and spectral accuracy of laser spectroscopy with ion mobility mass spectrometry and combines the benefits of high sensitivity with the “simplicity” of an optical probe such as in laser-induced fluorescence spectroscopy. Its main idea is to detect the products of resonant optical excitations not based on fluorescent light as usual, but based on their characteristic drift time for a particle detector.
In their theoretical work, the researchers focused on a self-charged lawrencium, element 103, and on its lighter chemical counterpart. But the concept offers unparalleled access to laser spectroscopy of many other monoatomic ions around the periodic table, in particular transition metals including high-temperature refractory metals and elements beyond the lawrencium. . Other ionic species such as triple-charged thorium should also be met by the LRC approach. In addition, the method makes it possible to optimize the signal-to-noise ratios and thus speed up ion mobility spectrometry, state-selected ion chemistry, and other applications.
Dr Mustapha Laatiaoui entered Johannes Gutenberg University Mainz and the Helmholtz Mainz Institute (HIM) in February 2018. At the end of 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 on the heaviest elements using laser spectroscopy and ion mobility spectroscopy The present publications also included work that Laatiaoui had previously done at SGI Helmholtzzentrum für Schwerionenforschung in Darmstadt and at KU Leuven in Belgium.
“Superheavy Element Laser Resonance Chromatography” by Mustapha Laatiaoui, Alexei A. Buchachenko and Larry A. Viehland, July 10, 2020, Physical Review Letters.
DOI: 10.1103 / PhysRevLett.125.023002
“Exploitation of transport properties for the detection of optical pumping in heavy ions” by Mustapha Laatiaoui, Alexei A. Buchachenko and Larry A. Viehland, 10 July 2020, Physical Review A.
DOI: 10.1103 / PhysRevA.102.013106
This work was carried out 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.