Search results for "Nobel"
showing 10 items of 41 documents
Laser spectroscopy studies on nobelium
2017
Laser spectroscopy of the heaviest elements provides high-precision data on their atomic and nuclear properties. For example, atomic level energies and ionization potentials allow us to probe the influence of relativistic effects on their atomic structure and to benchmark state-of-the-art atomic structure calculations. In addition, it offers an alternative route to determine nuclear properties like spins, magnetic moments and quadrupole moments in a nuclear model-independent way. Recently, a sensitive method based on resonant laser ionization has been applied to nobelium isotopes around N = 152 at GSI Darmstadt. In pioneering experiments, several atomic states have been identified extending…
Effects of climate change and land use intensification on regional biological soil crust cover and composition in southern Africa
2022
Biological soil crusts (biocrusts) form a regular and relevant feature in drylands, as they stabilize the soil, fix nutrients, and influence water cycling. However, biocrust forming organisms have been shown to be dramatically vulnerable to climate and land use change occurring in these regions. In this study, we used Normalized Difference Vegetation Index (NDVI) data of biocrust-dominated pixels (NDVIbiocrust) obtained from hyperspectral and LANDSAT-7 data to analyse biocrust development over time and to forecast future NDVIbiocrust development under different climate change and livestock density scenarios in southern Africa. We validated these results by analysing the occurrence and compo…
Deformations and quasiparticle spectra of nuclei in the nobelium region
2013
We have performed self-consistent Skyrme Hartree-Fock-Bogolyubov calculations for nuclei close to $^{254}$No. Self-consistent deformations, including $\beta_{2,4,6,8}$ as functions of the rotational frequency, were determined for even-even nuclei $^{246,248,250}$Fm, $^{252,254}$No, and $^{256}$Rf. The quasiparticle spectra for N=151 isotones and Z=99 isotopes were calculated and compared with experimental data and the results of Woods-Saxon calculations. We found that our calculations give high-order deformations similar to those obtained for the Woods-Saxon potential, and that the experimental quasiparticle energies are reasonably well reproduced.
Zvaigžņotā Debess: 2016, Vasara (232)
2016
Contents: “ZVAIGŽŅOTĀ DEBESS” FORTY YEARS AGO: A.Balklavs. New Studies and Conclusions on Nucleus of the Galaxy (abridged) ; U.Dzērvītis. Discussion on Planetary System of Barnard’s Star Continues (abridged) ; M.Eliāss. Meeting of Solar Radio Radiation Section (abridged) ; DEVELOPMENTS in SCIENCE: O.Dumbrājs. Neutrino Oscillations: from the Outset to the Nobel Prize ; R.Misa. Conversation with Andris Ambainis on Quantum Computing Science ; DISCOVERIES: F.Gahbauer. First Direct Detection of Gravitational Waves ; I.Pundure. ATLASGAL Survey of Milky Way Completed ; SPACE RESEARCH and EXPLORATION: J.Jaunbergs. The Story of Pluto’s Satellites ; K.Schwartz. Conducting Ice and Magnetic Field of Ur…
Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy
2018
Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Laser spectroscopy in combination with modern atomic structure calculations is now able to probe these moments directly, in a comprehensive and nuclear-model-independent way. Here we report on unique access to the differential mean-square charge radii of ^{252,253,254}No, and therefore to changes in nuclear size and shape. State-of-the-art nuclear density functional calculations describe well the changes in nuclear charge radii in the region of the heavy actinides, indicating an appreciable central depression in the deformed proton densi…
Cronache dalla terra dei più felici al mondo
2023
Translation into Italian of Nobel Laureate Wole Soyinka's 2021 novel Chronicles from the Land of the Happiest People on Earth. Soyinka's Chronicles - published 48 years after his latest novel, The Interpreters - offers a fictional fresco of contemporary Nigeria, a country ridden by political and moral corruption. During the latest political campaigns, Dr. Menka finds out that some colleagues at the hospital where he works sell body parts for ritualistic reasons. Afflicted by such an unexpected discovery, he shares the news with his oldest college friend, bon viveur, star engineer, and Yoruba royal Duyole Pitan-Payne, who is about to leave the country to assume a prestigious post at the Unit…
Recent developments for high-precision mass measurements of the heaviest elements at SHIPTRAP
2013
Abstract Atomic nuclei far from stability continue to challenge our understanding. For example, theoretical models have predicted an “island of stability” in the region of the superheavy elements due to the closure of spherical proton and neutron shells. Depending on the model, these are expected at Z = 114, 120 or even 126 and N = 172 or 184. Valuable information on the road to the island of stability is derived from high-precision mass measurements, which give direct access to binding energies of short-lived trans-uranium nuclei. Recently, direct mass measurements at SHIPTRAP have been extended to nobelium and lawrencium isotopes around the deformed shell gap N = 152. In order to further …
Rotational properties of nuclei aroundNo254investigated using a spectroscopic-quality Skyrme energy density functional
2014
Background: Nuclei in the $Z\ensuremath{\approx}100$ mass region represent the heaviest systems where detailed spectroscopic information is experimentally available. Although microscopic-macroscopic and self-consistent models have achieved great success in describing the data in this mass region, a fully satisfying precise theoretical description is still missing.Purpose: By using fine-tuned parametrizations of the energy density functionals, the present work aims at an improved description of the single-particle properties and rotational bands in the nobelium region. Such locally optimized parametrizations may have better properties when extrapolating towards the superheavy region.Methods:…
First Ionization Potentials of Fm, Md, No, and Lr
2018
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 clear…
A gas-jet apparatus for high-resolution laser spectroscopy on the heaviest elements at SHIP
2020
© 2019 Elsevier B.V. Laser spectroscopy enables the determination of fundamental atomic and nuclear properties with high precision. In view of the low production rates of the heaviest elements, a high total efficiency is a crucial requirement for any experimental setup to be used in on-line experiments. The setup requires the use of gas stopping techniques to slow down the radionuclides of interest. In previous studies laser spectroscopy was performed inside a gas-filled stopping cell with a limited spectral resolution of a few GHz. Collisional broadening inside stopping cells ultimately limits the precision of laser spectroscopic studies and hampers in particular hyperfine spectroscopy. Th…