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Y Kaneya - One of the best experts on this subject based on the ideXlab platform.
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first ionization potentials of fm md no and lr verification of filling up of 5f electrons and confirmation of the actinide series
Journal of the American Chemical Society, 2018Co-Authors: T K Sato, M Asai, Anastasia Borschevsky, Y Kaneya, R Beerwerth, H Makii, Akina Mitsukai, Y. NagameAbstract:We report the first ionization potentials (IP1) of the heavy actinides, fermium (Fm, atomic number Z = 100), mendelevium (Md, Z = 101), nobelium (No, Z = 102), and Lawrencium (Lr, Z = 103), determined using a method based on a surface ionization process coupled to an online mass separation technique in an atom-at-a-time regime. The measured IP1 values agree well with those predicted by state-of-the-art relativistic calculations performed alongside the present measurements. Similar to the well-established behavior for the lanthanides, the IP1 values of the heavy actinides up to No increase with filling up the 5f orbital, while that of Lr is the lowest among the actinides. These results clearly demonstrate that the 5f orbital is fully filled at No with the [Rn]5f147s2 configuration and that Lr has a weakly bound electron outside the No core. In analogy to the lanthanide series, the present results unequivocally verify that the actinide series ends with Lr.
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Measurement of the First Ionization Potential of Lawrencium (Lr, Z=103) by a Surface Ionization
2016Co-Authors: T K Sato, M Asai, T Stora, Y Kaneya, Kazuaki Tsukada, A. Toyoshima, A. Osa, S. Ichikawa, Y. Nagame, A. BorschevskyAbstract:Relativistic effects influence the electronic structure of heavy elements. The ground-state electronic configuration of the heaviest actinide, Lawrencium (Lr, Z = 103), is predicted to be [Rn]5f147s27p1/2, which is different from that of the lanthanide homolog lutetium (Lu) [Xe]4f146s25d. The reason for this change is that the 7p orbital of Lr is stabilized below the 6d orbital by strong relativistic effects [1]. The first ionization potential (IP1), one of the most fundamental physical and chemical properties of an element, gives direct information about the binding energy of an electron in the outermost electronic orbital of an atom. Accurate IP1 values of heavy elements provide crucial tests for our understanding of their electronic structure. IP1 values of heavy elements with Z ≧ 100, however, could not be determined experimentally, because production rates drastically decrease fo
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first ionization potential of the heaviest actinide Lawrencium element 103
European Physical Journal Web of Conferences, 2016Co-Authors: T K Sato, M Asai, Anastasia Borschevsky, T Stora, Nozomi Sato, Y Kaneya, Kazuaki Tsukada, Christoph E Dullmann, K EberhardtAbstract:The first ionization potential (IP1 ) of element 103, Lawrencium (Lr), has been successfully determined for the first time by using a newly developed method based on a surface ionization process. The measured IP 1 value is 4.9630.08 0.07 eV. This value is the smallest among those of actinide elements and is in excellent agreement with the value of 4.963(15) eV predicted by state-of-the-art relativistic calculations also performed in this work. Our results strongly support that the Lr atom has an electronic configuration of [Rn]7s 2 5f 14 7p 1 1/2 , which is influenced by strong relativistic effects. The present work provides a reliable benchmark for theoretical calculations and also opens the way for studies on atomic properties of heavy elements with atomic number Z > 100. Moreover, the present achievement has triggered a controversy on the position of lutetium (Lu) and Lr in the Periodic Table of Elements.
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measurement of the first ionization potential of Lawrencium element 103
Nature, 2015Co-Authors: T K Sato, Ch. E. Düllmann, M Asai, Anastasia Borschevsky, T Stora, Nozomi Sato, Y Kaneya, Kazuaki Tsukada, K EberhardtAbstract:Lawrencium, with atomic number 103, has an isotope with a half-life of 27 seconds; even so, its first ionization potential has now been measured on an atom-at-a-time scale and agrees well with state-of-the-art theoretical calculations that include relativistic effects. The most dramatic modern revision of Mendeleev's periodic table of elements came in 1944 when Glenn T. Seaborg placed a new series of elements, the actinides (atomic numbers 89–103), below the lanthanides. In this issue of Nature, Yuichiro Nagame and colleagues report the first measurement of one of the basic atomic properties of element 103 (Lawrencium), namely its first ionization potential. Lawrencium is only accessible via atom-at-a-time synthesis in heavy-ion accelerators, so experimental investigations of its properties are rare. Nagame and colleagues were able to reduce the number of atoms required to measure the ionization potential from billions to thousands, and these results — in agreement with the latest theoretical calculations — show that the last valence electron in Lawrencium is the most weakly bound one in all actinides and any other element beyond group 1 of the periodic table. This signature — in a region of the periodic table where the sheer size of the atoms means that relativistic effects play a crucial role — confirms the end of the actinide series at element 103. The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row—including the actinides—even affecting ground-state configurations1,2. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time3,4,5. Here we report that the experimentally obtained IP1 of the heaviest actinide, Lawrencium (Lr, atomic number 103), is electronvolts. The IP1 of Lr was measured with 256Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.
T K Sato - One of the best experts on this subject based on the ideXlab platform.
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first ionization potentials of fm md no and lr verification of filling up of 5f electrons and confirmation of the actinide series
Journal of the American Chemical Society, 2018Co-Authors: T K Sato, M Asai, Anastasia Borschevsky, Y Kaneya, R Beerwerth, H Makii, Akina Mitsukai, Y. NagameAbstract:We report the first ionization potentials (IP1) of the heavy actinides, fermium (Fm, atomic number Z = 100), mendelevium (Md, Z = 101), nobelium (No, Z = 102), and Lawrencium (Lr, Z = 103), determined using a method based on a surface ionization process coupled to an online mass separation technique in an atom-at-a-time regime. The measured IP1 values agree well with those predicted by state-of-the-art relativistic calculations performed alongside the present measurements. Similar to the well-established behavior for the lanthanides, the IP1 values of the heavy actinides up to No increase with filling up the 5f orbital, while that of Lr is the lowest among the actinides. These results clearly demonstrate that the 5f orbital is fully filled at No with the [Rn]5f147s2 configuration and that Lr has a weakly bound electron outside the No core. In analogy to the lanthanide series, the present results unequivocally verify that the actinide series ends with Lr.
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Measurement of the First Ionization Potential of Lawrencium (Lr, Z=103) by a Surface Ionization
2016Co-Authors: T K Sato, M Asai, T Stora, Y Kaneya, Kazuaki Tsukada, A. Toyoshima, A. Osa, S. Ichikawa, Y. Nagame, A. BorschevskyAbstract:Relativistic effects influence the electronic structure of heavy elements. The ground-state electronic configuration of the heaviest actinide, Lawrencium (Lr, Z = 103), is predicted to be [Rn]5f147s27p1/2, which is different from that of the lanthanide homolog lutetium (Lu) [Xe]4f146s25d. The reason for this change is that the 7p orbital of Lr is stabilized below the 6d orbital by strong relativistic effects [1]. The first ionization potential (IP1), one of the most fundamental physical and chemical properties of an element, gives direct information about the binding energy of an electron in the outermost electronic orbital of an atom. Accurate IP1 values of heavy elements provide crucial tests for our understanding of their electronic structure. IP1 values of heavy elements with Z ≧ 100, however, could not be determined experimentally, because production rates drastically decrease fo
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First successful ionization of Lawrencium by surface ionization process
2016Co-Authors: T K Sato, M Asai, Kazuaki Tsukada, A. Toyoshima, A. OsaAbstract:The first ionization potential (IP) is one of the fundamental physical and chemical properties of an element. It directly reflects the electronic configuration of the element. The relativistic effects affect the electronic configuration and would be noticeable for the heaviest elements. With an experimentally determined IP value of heavy elements, therefore, we can contribute to a better understanding of shell effects and how relativistic effects play a role in the electronic structure of heavy atoms. The ground-state electronic configuration of the heaviest actinide, Lawrencium (Lr, the atomic number Z = 103), is predicted to be [Rn]5f147s27p1/2, which is different from that of the lanthanide homolog lutetium (Lu) [Xe]4f146s25d. The reason for this change in the ground-state configuration is that the 7p orbital of Lr is stabilized below the 6d orbital by strong relativistic effects [1]. The weakly-bound outermost electro
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first ionization potential of the heaviest actinide Lawrencium element 103
European Physical Journal Web of Conferences, 2016Co-Authors: T K Sato, M Asai, Anastasia Borschevsky, T Stora, Nozomi Sato, Y Kaneya, Kazuaki Tsukada, Christoph E Dullmann, K EberhardtAbstract:The first ionization potential (IP1 ) of element 103, Lawrencium (Lr), has been successfully determined for the first time by using a newly developed method based on a surface ionization process. The measured IP 1 value is 4.9630.08 0.07 eV. This value is the smallest among those of actinide elements and is in excellent agreement with the value of 4.963(15) eV predicted by state-of-the-art relativistic calculations also performed in this work. Our results strongly support that the Lr atom has an electronic configuration of [Rn]7s 2 5f 14 7p 1 1/2 , which is influenced by strong relativistic effects. The present work provides a reliable benchmark for theoretical calculations and also opens the way for studies on atomic properties of heavy elements with atomic number Z > 100. Moreover, the present achievement has triggered a controversy on the position of lutetium (Lu) and Lr in the Periodic Table of Elements.
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measurement of the first ionization potential of Lawrencium element 103
Nature, 2015Co-Authors: T K Sato, Ch. E. Düllmann, M Asai, Anastasia Borschevsky, T Stora, Nozomi Sato, Y Kaneya, Kazuaki Tsukada, K EberhardtAbstract:Lawrencium, with atomic number 103, has an isotope with a half-life of 27 seconds; even so, its first ionization potential has now been measured on an atom-at-a-time scale and agrees well with state-of-the-art theoretical calculations that include relativistic effects. The most dramatic modern revision of Mendeleev's periodic table of elements came in 1944 when Glenn T. Seaborg placed a new series of elements, the actinides (atomic numbers 89–103), below the lanthanides. In this issue of Nature, Yuichiro Nagame and colleagues report the first measurement of one of the basic atomic properties of element 103 (Lawrencium), namely its first ionization potential. Lawrencium is only accessible via atom-at-a-time synthesis in heavy-ion accelerators, so experimental investigations of its properties are rare. Nagame and colleagues were able to reduce the number of atoms required to measure the ionization potential from billions to thousands, and these results — in agreement with the latest theoretical calculations — show that the last valence electron in Lawrencium is the most weakly bound one in all actinides and any other element beyond group 1 of the periodic table. This signature — in a region of the periodic table where the sheer size of the atoms means that relativistic effects play a crucial role — confirms the end of the actinide series at element 103. The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row—including the actinides—even affecting ground-state configurations1,2. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time3,4,5. Here we report that the experimentally obtained IP1 of the heaviest actinide, Lawrencium (Lr, atomic number 103), is electronvolts. The IP1 of Lr was measured with 256Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.
Michael Block - One of the best experts on this subject based on the ideXlab platform.
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Filament studies for laser spectroscopy on Lawrencium
Hyperfine Interactions, 2020Co-Authors: Tobias Murböck, Sebastian Raeder, Premaditya Chhetri, Katerine Diaz, Mustapha Laatiaoui, Francesca Giacoppo, Michael BlockAbstract:The sensitive RAdiation Detected Resonance Ionization Spectroscopy (RADRIS) technique enabled the study of the atomic structure of the element nobelium (No, Z = 102) for the first time. The prospect of accessing the next element, Lawrencium (Lr, Z = 103), depends on the efficiency and speed of evaporation of sample atoms from a filament catcher. To determine the desorption properties with respect to the requirements for the RADRIS technique, an off-line set-up to characterize filament catchers was developed. Using the iso-electronic homologue lutetium (Lu, Z = 71) different filament materials were studied with respect to the required desorption temperatures and the background from surface ionization.
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Atom-at-a-time laser resonance ionization spectroscopy of nobelium
Nature, 2016Co-Authors: Mustapha Laatiaoui, Michael Block, Ch. E. Düllmann, Premaditya Chhetri, Werner Lauth, Hartmut Backe, Dieter Ackermann, Bradley Cheal, Piet Van Duppen, Julia EvenAbstract:Characterizing the heaviest elements in the periodic table is a gruelling task because they are radioactive, exist only for split seconds at a time and need to be artificially produced in sufficient quantities by complicated procedures. The heaviest element that has been characterized by optical spectroscopy is fermium, which has an atomic number of 100. Mustapha Laatiaoui et al . extend the methods used for fermium to perform optical spectroscopy on nobelium (atomic number 102). Through laser resonance ionization spectroscopy, they identify the ground-state transition of the atom and manage to investigate highly excited states called Rydberg states. This allows them to determine an upper limit for the atomic ionization potential of nobelium. This study opens the door to the characterization of even heavier elements such as Lawrencium using optical spectroscopy. Resonance ionization spectroscopy of nobelium (atomic number 102) reveals its ground-state transition and an upper limit for its ionization potential, paving the way to characterizing even heavier elements via optical spectroscopy. Optical spectroscopy of a primordial isotope has traditionally formed the basis for understanding the atomic structure of an element. Such studies have been conducted for most elements^ 1 and theoretical modelling can be performed to high precision^ 2 , 3 , taking into account relativistic effects that scale approximately as the square of the atomic number. However, for the transfermium elements (those with atomic numbers greater than 100), the atomic structure is experimentally unknown. These radioactive elements are produced in nuclear fusion reactions at rates of only a few atoms per second at most and must be studied immediately following their production^ 4 , which has so far precluded their optical spectroscopy. Here we report laser resonance ionization spectroscopy of nobelium (No; atomic number 102) in single-atom-at-a-time quantities, in which we identify the ground-state transition ^1S_0 ^1P_1. By combining this result with data from an observed Rydberg series, we obtain an upper limit for the ionization potential of nobelium. These accurate results from direct laser excitations of outer-shell electrons cannot be achieved using state-of-the-art relativistic many-body calculations^ 5 , 6 , 7 , 8 that include quantum electrodynamic effects, owing to large uncertainties in the modelled transition energies of the complex systems under consideration. Our work opens the door to high-precision measurements of various atomic and nuclear properties of elements heavier than nobelium, and motivates future theoretical work.
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Direct Mapping of Nuclear Shell Effects in the Heaviest Elements
Science (New York N.Y.), 2012Co-Authors: E. Minaya Ramirez, D. Ackermann, Klaus Blaum, Michael Block, C. Droese, Ch. E. Düllmann, M. Dworschak, Martin Eibach, Sergey Eliseev, Emma HaettnerAbstract:Quantum-mechanical shell effects are expected to strongly enhance nuclear binding on an “island of stability” of superheavy elements. The predicted center at proton number Z = 114, 120, or 126 and neutron number N = 184 has been substantiated by the recent synthesis of new elements up to Z = 118. However, the location of the center and the extension of the island of stability remain vague. High-precision mass spectrometry allows the direct measurement of nuclear binding energies and thus the determination of the strength of shell effects. Here, we present such measurements for nobelium and Lawrencium isotopes, which also pin down the deformed shell gap at N = 152.
Ch. E. Düllmann - One of the best experts on this subject based on the ideXlab platform.
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Atom-at-a-time laser resonance ionization spectroscopy of nobelium
Nature, 2016Co-Authors: Mustapha Laatiaoui, Michael Block, Ch. E. Düllmann, Premaditya Chhetri, Werner Lauth, Hartmut Backe, Dieter Ackermann, Bradley Cheal, Piet Van Duppen, Julia EvenAbstract:Characterizing the heaviest elements in the periodic table is a gruelling task because they are radioactive, exist only for split seconds at a time and need to be artificially produced in sufficient quantities by complicated procedures. The heaviest element that has been characterized by optical spectroscopy is fermium, which has an atomic number of 100. Mustapha Laatiaoui et al . extend the methods used for fermium to perform optical spectroscopy on nobelium (atomic number 102). Through laser resonance ionization spectroscopy, they identify the ground-state transition of the atom and manage to investigate highly excited states called Rydberg states. This allows them to determine an upper limit for the atomic ionization potential of nobelium. This study opens the door to the characterization of even heavier elements such as Lawrencium using optical spectroscopy. Resonance ionization spectroscopy of nobelium (atomic number 102) reveals its ground-state transition and an upper limit for its ionization potential, paving the way to characterizing even heavier elements via optical spectroscopy. Optical spectroscopy of a primordial isotope has traditionally formed the basis for understanding the atomic structure of an element. Such studies have been conducted for most elements^ 1 and theoretical modelling can be performed to high precision^ 2 , 3 , taking into account relativistic effects that scale approximately as the square of the atomic number. However, for the transfermium elements (those with atomic numbers greater than 100), the atomic structure is experimentally unknown. These radioactive elements are produced in nuclear fusion reactions at rates of only a few atoms per second at most and must be studied immediately following their production^ 4 , which has so far precluded their optical spectroscopy. Here we report laser resonance ionization spectroscopy of nobelium (No; atomic number 102) in single-atom-at-a-time quantities, in which we identify the ground-state transition ^1S_0 ^1P_1. By combining this result with data from an observed Rydberg series, we obtain an upper limit for the ionization potential of nobelium. These accurate results from direct laser excitations of outer-shell electrons cannot be achieved using state-of-the-art relativistic many-body calculations^ 5 , 6 , 7 , 8 that include quantum electrodynamic effects, owing to large uncertainties in the modelled transition energies of the complex systems under consideration. Our work opens the door to high-precision measurements of various atomic and nuclear properties of elements heavier than nobelium, and motivates future theoretical work.
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measurement of the first ionization potential of Lawrencium element 103
Nature, 2015Co-Authors: T K Sato, Ch. E. Düllmann, M Asai, Anastasia Borschevsky, T Stora, Nozomi Sato, Y Kaneya, Kazuaki Tsukada, K EberhardtAbstract:Lawrencium, with atomic number 103, has an isotope with a half-life of 27 seconds; even so, its first ionization potential has now been measured on an atom-at-a-time scale and agrees well with state-of-the-art theoretical calculations that include relativistic effects. The most dramatic modern revision of Mendeleev's periodic table of elements came in 1944 when Glenn T. Seaborg placed a new series of elements, the actinides (atomic numbers 89–103), below the lanthanides. In this issue of Nature, Yuichiro Nagame and colleagues report the first measurement of one of the basic atomic properties of element 103 (Lawrencium), namely its first ionization potential. Lawrencium is only accessible via atom-at-a-time synthesis in heavy-ion accelerators, so experimental investigations of its properties are rare. Nagame and colleagues were able to reduce the number of atoms required to measure the ionization potential from billions to thousands, and these results — in agreement with the latest theoretical calculations — show that the last valence electron in Lawrencium is the most weakly bound one in all actinides and any other element beyond group 1 of the periodic table. This signature — in a region of the periodic table where the sheer size of the atoms means that relativistic effects play a crucial role — confirms the end of the actinide series at element 103. The chemical properties of an element are primarily governed by the configuration of electrons in the valence shell. Relativistic effects influence the electronic structure of heavy elements in the sixth row of the periodic table, and these effects increase dramatically in the seventh row—including the actinides—even affecting ground-state configurations1,2. Atomic s and p1/2 orbitals are stabilized by relativistic effects, whereas p3/2, d and f orbitals are destabilized, so that ground-state configurations of heavy elements may differ from those of lighter elements in the same group. The first ionization potential (IP1) is a measure of the energy required to remove one valence electron from a neutral atom, and is an atomic property that reflects the outermost electronic configuration. Precise and accurate experimental determination of IP1 gives information on the binding energy of valence electrons, and also, therefore, on the degree of relativistic stabilization. However, such measurements are hampered by the difficulty in obtaining the heaviest elements on scales of more than one atom at a time3,4,5. Here we report that the experimentally obtained IP1 of the heaviest actinide, Lawrencium (Lr, atomic number 103), is electronvolts. The IP1 of Lr was measured with 256Lr (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator. The measured IP1 is in excellent agreement with the value of 4.963(15) electronvolts predicted here by state-of-the-art relativistic calculations. The present work provides a reliable benchmark for theoretical calculations and also opens the way for IP1 measurements of superheavy elements (that is, transactinides) on an atom-at-a-time scale.
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Direct Mapping of Nuclear Shell Effects in the Heaviest Elements
Science (New York N.Y.), 2012Co-Authors: E. Minaya Ramirez, D. Ackermann, Klaus Blaum, Michael Block, C. Droese, Ch. E. Düllmann, M. Dworschak, Martin Eibach, Sergey Eliseev, Emma HaettnerAbstract:Quantum-mechanical shell effects are expected to strongly enhance nuclear binding on an “island of stability” of superheavy elements. The predicted center at proton number Z = 114, 120, or 126 and neutron number N = 184 has been substantiated by the recent synthesis of new elements up to Z = 118. However, the location of the center and the extension of the island of stability remain vague. High-precision mass spectrometry allows the direct measurement of nuclear binding energies and thus the determination of the strength of shell effects. Here, we present such measurements for nobelium and Lawrencium isotopes, which also pin down the deformed shell gap at N = 152.
Mustapha Laatiaoui - One of the best experts on this subject based on the ideXlab platform.
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Filament studies for laser spectroscopy on Lawrencium
Hyperfine Interactions, 2020Co-Authors: Tobias Murböck, Sebastian Raeder, Premaditya Chhetri, Katerine Diaz, Mustapha Laatiaoui, Francesca Giacoppo, Michael BlockAbstract:The sensitive RAdiation Detected Resonance Ionization Spectroscopy (RADRIS) technique enabled the study of the atomic structure of the element nobelium (No, Z = 102) for the first time. The prospect of accessing the next element, Lawrencium (Lr, Z = 103), depends on the efficiency and speed of evaporation of sample atoms from a filament catcher. To determine the desorption properties with respect to the requirements for the RADRIS technique, an off-line set-up to characterize filament catchers was developed. Using the iso-electronic homologue lutetium (Lu, Z = 71) different filament materials were studied with respect to the required desorption temperatures and the background from surface ionization.
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Atom-at-a-time laser resonance ionization spectroscopy of nobelium
Nature, 2016Co-Authors: Mustapha Laatiaoui, Michael Block, Ch. E. Düllmann, Premaditya Chhetri, Werner Lauth, Hartmut Backe, Dieter Ackermann, Bradley Cheal, Piet Van Duppen, Julia EvenAbstract:Characterizing the heaviest elements in the periodic table is a gruelling task because they are radioactive, exist only for split seconds at a time and need to be artificially produced in sufficient quantities by complicated procedures. The heaviest element that has been characterized by optical spectroscopy is fermium, which has an atomic number of 100. Mustapha Laatiaoui et al . extend the methods used for fermium to perform optical spectroscopy on nobelium (atomic number 102). Through laser resonance ionization spectroscopy, they identify the ground-state transition of the atom and manage to investigate highly excited states called Rydberg states. This allows them to determine an upper limit for the atomic ionization potential of nobelium. This study opens the door to the characterization of even heavier elements such as Lawrencium using optical spectroscopy. Resonance ionization spectroscopy of nobelium (atomic number 102) reveals its ground-state transition and an upper limit for its ionization potential, paving the way to characterizing even heavier elements via optical spectroscopy. Optical spectroscopy of a primordial isotope has traditionally formed the basis for understanding the atomic structure of an element. Such studies have been conducted for most elements^ 1 and theoretical modelling can be performed to high precision^ 2 , 3 , taking into account relativistic effects that scale approximately as the square of the atomic number. However, for the transfermium elements (those with atomic numbers greater than 100), the atomic structure is experimentally unknown. These radioactive elements are produced in nuclear fusion reactions at rates of only a few atoms per second at most and must be studied immediately following their production^ 4 , which has so far precluded their optical spectroscopy. Here we report laser resonance ionization spectroscopy of nobelium (No; atomic number 102) in single-atom-at-a-time quantities, in which we identify the ground-state transition ^1S_0 ^1P_1. By combining this result with data from an observed Rydberg series, we obtain an upper limit for the ionization potential of nobelium. These accurate results from direct laser excitations of outer-shell electrons cannot be achieved using state-of-the-art relativistic many-body calculations^ 5 , 6 , 7 , 8 that include quantum electrodynamic effects, owing to large uncertainties in the modelled transition energies of the complex systems under consideration. Our work opens the door to high-precision measurements of various atomic and nuclear properties of elements heavier than nobelium, and motivates future theoretical work.