Laser resonance chromatography will initially be used to investigate lawrence, element 103. Credit: Mustapha Laatiaoui
Combining physics and chemistry methodologies for super heavy element optical spectroscopy.
Superheavy elements are intriguing nuclear and atomic quantum systems that challenge experimental sounding since they do not occur in nature and, when synthesized, disappear within seconds. Boosting cutting-edge atomic physics research towards these elements requires innovative 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 of Mainz (JGU) culminated in a proposal for optical spectroscopy: the so-called laser resonance chromatography (LRC ) should allow such investigations even in production quantities per minute. The proposal has recently been published in two articles in Physical Review Letters and Physical Review A.
Super Heavy Elements (SHE) are located at the bottom of the periodic table of elements. They represent fertile ground for developing an understanding of how such exotic atoms can exist and function when an overwhelming number of electrons are brought together in atomic shells and protons and neutrons in the nucleus. Information about its electronic structure can be obtained from light spectroscopy experiments that reveal element-specific emission spectra. These spectra are powerful reference points for modern calculations of atomic models and could be useful, for example, when looking for traces of even heavier elements, which could be created in neutron star fusion events.
The LRC approach combines different methods
Although SHEs were discovered decades ago, their investigation using light spectroscopy tools lacks much of the synthesis. This is because they occur at extremely low rates at which traditional methods simply don’t work. So far, light spectroscopy ends at the nobelium, item 102 on the periodic table. “Current techniques are at the limit of what is feasible,” Laatiaoui explained. Starting with the next heaviest element, the physicochemical properties change abruptly, making it impossible to provide samples in suitable atomic states. “
Laser resonance chromatography is based on optical excitations of ions and the subsequent detection of their arrival at the detector. Credit: Mustapha Laatiaoui
Along with his research colleagues, the physicist has developed the new LRC approach in light spectroscopy. This combines the selectivity of elements and the spectral precision of laser spectroscopy with ion mobility mass spectrometry and combines the benefits of high sensitivity with the “simplicity” of optical scanning as in laser-induced fluorescence spectroscopy. Their key idea is to detect the resonant optical excitation products not on the basis of fluorescent light as usual, but on the basis of their characteristic shunt time to a particle detector.
In their theoretical work, the researchers focused on the individually charged lawrencio, element 103, and its lighter chemical counterpart. But the concept offers unrivaled access to laser spectroscopy of many other monatomic ions through the periodic table, in particular transition metals, including high-temperature refractory metals and elements beyond lawrenzium. Other ionic species like triple charged thorium will also be within the LRC approach. Furthermore, the method allows to optimize signal / noise ratios and, therefore, to facilitate ion mobility spectrometry, state selected ion chemistry and other applications.
Dr. Mustapha Laatiaoui arrived at the Johannes Gutenberg University of 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 grants from most valuable funding from the European Union. , for his research on the heaviest elements using laser spectroscopy and ion mobility spectroscopy. Current publications also included work that Laatiaoui had previously carried out at GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt and at KU Leuven in Belgium.
References
“Super Heavy 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 Detection of Optical Pumping in Heavy Ions” by Mustapha Laatiaoui, Alexei A. Buchachenko and Larry A. Viehland, July 10, 2020, Physical Review A.
DOI: 10.1103 / PhysRevA.102.013106
This work was done in cooperation with Alexei A. Buchachenko of the Skolkovo Institute of Science and Technology and the Institute for Problems of Chemical Physics, both in Moscow, Russia, and Larry A. Viehland of Chatham University, Pittsburgh, USA.
