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Nucleosynthesis, Cosmic Radiation, and the Universe
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
A supernova is a star that is heavier than the Sun. When it runs out of hydrogen fuel, it contracts under its own gravitational force and implodes. The implosion is accompanied by an instantaneous, ultra intense burst of neutrons when the outer layers collapse. The extremely high pressure inside the stellar core supplies a further neutron flash by converting the protons into neutrons. The burst lasts for a few seconds and provides an enormous number of neutrons. The target nucleus captures successively dozens of neutrons within a minute fraction of a second and the gap appearing in the s-process due to short-lived nuclides is overcome by the r-process. This allows the nucleosynthesis of all heavier chemical elements including the hypothetical superheavy elements.
Anion-exchange Experiment of Zr, Hf, and Th in HNO3 and Quantum Chemical Study on the Nitrate Complexes toward Chemical Research on Element 104, Rf
Published in Solvent Extraction and Ion Exchange, 2021
Eisuke Watanabe, Yoshitaka Kasamatsu, Takuya Yokokita, Sho Hayami, Katsuma Tonai, Hidemi Ninomiya, Narumi Kondo, Yudai Shigekawa, Hiromitsu Haba, Yasutaka Kitagawa, Masayoshi Nakano, Atsushi Shinohara
Elements with atomic number Z ≥ 104 are called superheavy elements (SHEs) and it is suggested that their electronic states may be different from those of homologues due to strong relativistic effects.[1,2] In other words, the chemical properties of SHEs may deviate from the periodicity among its homologues in the periodic table, the basic principle of chemistry discovered by D. Mendeleev over 150 years ago. However, because of the difficulty in executing chemical experiments with short-lived isotopes, the chemical properties of the SHEs are primarily unknown. SHEs are synthesized at a production rate of less than a few atoms per minute by heavy-ion induced nuclear reactions using an accelerator, and their nuclei have half-lives shorter than a few minutes. Therefore, SHEs must be handled as one atom at a time,[3] and so typical chemical spectroscopic analysis targeting the macro amount of atoms, such as NMR, cannot be applied to the chemistry of SHEs. The atomic-physical technique such as laser- or surface-ionization has been recently applied to heavy actinides with Z ≤ 103[4,5] and expected to be used for SHEs.
Chemistry of superheavy transition metals
Published in Journal of Coordination Chemistry, 2022
For a long time common wisdom was that some elements are useless (and also frightening). But even superheavy elements one day may find useful applications if their most stable isotopes are produced in reasonable amounts. Time will tell if the economic cost of this scientific venture is sustainable or we should pursue different priorities.