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Gas chromatographic investigations of volatile transactinides

English title Gas chromatographic investigations of volatile transactinides
Applicant Steinegger Patrick Julian Rolf
Number 196981
Funding scheme Project funding
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Physical Chemistry
Start/End 01.01.2021 - 31.12.2024
Approved amount 659'015.00
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All Disciplines (2)

Discipline
Physical Chemistry
Nuclear Physics

Keywords (10)

superheavy elements; one-atom-at-a-time; thallium; nihonium; gas adsorption chromatography; vacuum adsorption chromatography; transactinides; online experiments; relativistic effects; high-temperature alpha-spectroscopy

Lay Summary (German)

Lead
Die Untersuchung physikalisch-chemischer Eigenschaften neu entdeckter, chemischer Elemente ist von jeher eine Aufgabe der Grundlagenforschung. Während dafür früher klassisch-chemische Methoden angewendet werden konnten, kommen heute ausschliesslich radiochemische Experimente zum Zuge. Inhalt dieser Forschungsarbeit ist die chemische Untersuchung von Nihonium (Nh, Z=113) mittels schneller Gaschromatographie im Bereich der Kontinuumsströmung als auch der Molekularströmung.
Lay summary
Inhalt dieses Forschungsprojekts ist die eindeutige, chemische Charakterisierung des neu entdeckten, chemischen Elements Nihonium (Nh, Z=113), ein Mitglied der sogenannten Superschweren Elemente (Z≥104). Das Projekt wird in zwei Teilen realisiert, beide mit dem Umfang einer eigenständigen Doktorarbeit. Während im ersten Teil die Verbindungsbildung in der Form des Monohydroxids erstrebt wird (d.h., NhOH), steht die Charakterisierung des Elementarzustandes von Nh im Zentrum des zweiten Teils dieses Projekts. Zu diesem Zweck wird die grundlegende Weiterentwicklung des Cryo OnLine Detektors (COLD) und der dazugehörigen Messtechnik pureCOLD anvisiert. Ziel dieser Weiterentwicklung ist es die Anwendbarkeit dieser Messmethode auf im Vergleich weniger flüchtige chemische Elemente oder deren Verbindungen auszuweiten. Dazu ist beispielsweise die Einbindung von Hochtemperatur-Detektoren für die Nuklearspektroskopie basierend auf Halbleitermaterialien mit grosser Bandlücke vorgesehen (z.B. hochreiner, einkristalliner Diamant oder 4H-SiC). Ebendiese Detektoren sind auch ein zentraler Bestandteil für die Realisierung der Vakuumchromatographie mit schwerer-flüchtigen Superschweren Elementen. Dieses, sich noch in der Entwicklungsphase befindliche, Experiment dient der Untersuchung kurzlebigster Radioisotope mit Halbwertszeiten unter einer Sekunde. Die hier vorgestellte Forschungsarbeit zielt daher nicht nur auf eine eindeutige chemische Charakterisierung von Nh ab, sondern legt gleichzeitig die Grundlage für die zukünftige Forschung mit kurzlebigeren und weniger flüchtigen Superschweren Elementen.
Direct link to Lay Summary Last update: 17.12.2020

Responsible applicant and co-applicants

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Associated projects

Number Title Start Funding scheme
162769 Gas chromatographic investigations of volatile transactinides 01.02.2016 Project funding

Abstract

By chemically characterizing transactinide elements, experimentalists follow in the footsteps of earliest chemists at the onset of science as we know it today. Concerned with the in-depth characterization of new elements and their compounds, these researchers laid the foundation for the periodic table of elements, one of the most central tools in natural sciences up to this day. The fundamental rules of periodicity, as the underlying ordering principle of Mendeleev’s table, have been tested for their validity during recent decades at its heavy end. An ever increasing impact of relativistic effects towards the bottom of the table changes the chemical and physical behavior of heavy elements in general and ultimately questions the table’s structure beyond element with the atomic number Z=123. It is only the cooperation between experimentalists and theoreticians, which allows scientist to measure and describe the impact of these effects. Whereas the theoretical description of certain atomic properties have attained a reasonably accurate level, quantum chemical computations of more complex problems, such as the adsorption behavior of a heavy element on a specific surface is still very difficult and thus, lack this accuracy. Nevertheless, state-of-the-art relativistic computational models based on density functional theory have considerably improved over the last years - also due to the input from experiments with transactinide elements. Produced only at the so-called one-atom-at-a-time level in heavy-ion-induced nuclear fusion evaporation reactions and owed to their short-lived radioactive nature, these elements demand for experiments tuned to highest speeds as well as efficiencies. Thus, for experimental chemists to venture on the study of transactinide elements translates to a multidisciplinary effort, involving several fundamental fields of science, namely nuclear- and radiochemistry, inorganic and physical chemistry as well as nuclear and atomic physics. Transactinide research has recently experienced yet another push with the start of operation of new, dedicated accelerator facilities from France and Germany over Russia to Japan. With increased intensities of the accelerators and improved transmission efficiencies of newest separators, experimentalists face a new era of unprecedented sensitivity in transactinide research.Herein we propose a project consisting of two individual parts, which will maintain the leading position of the Heavy Elements group at the Paul Scherrer Institute in the field of transactinide chemistry. After the successful chemistry experiments with transactinide elements copernicium and flerovium, advanced chromatography approaches can be applied for the first-ever unambiguous chemical characterization of nihonium. Therefore, the PhD thesis work in Part A focuses on the compound formation of nihonium monohydroxide and its subsequent characterization using gas-adsorption chromatography in the continuum flow regime. Online model investigations with the lighter homolog thallium will help to define the optimum experimental conditions. In parallel, a next generation development of gas-adsorption thermochromatography is targeted, using latest high-temperature alpha-spectroscopic technology based on silicon carbide. This development will almost triple the range of accessible adsorption enthalpies. Meanwhile, the second PhD thesis work in Part B is concerned with a first application of ultra-fast vacuum adsorption chromatography for the chemical characterization of nihonium in its elemental form. Our extensive groundwork and latest results render this technology ready for an application with transactinide elements. A most suited approach has to be evaluated, developed and tested in the form of a targeted solution for nuclear reaction products at low and high kinetic energies. The successful development of this technique will pave the way towards the future of chemical experiments beyond flerovium, with radionuclides featuring exclusively half-lives in the sub-second regime.The gathered results will be important benchmarks for theoretical models and thus increase our general understanding of how relativity governs physicochemical properties, not only of transactinide elements but all elements in general.
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