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Results for “NOBELIUM 254”

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DOE OSTI2019

Nuclear Data Sheets for A=254☆

Spectroscopic data for known A=254 nuclides (U, Cf, Es, Fm, Md, No, Lr and Rf) have been updated and re-evaluated, superseding the data presented in the previous evaluation 2005Bh12 published by A. Bhagwat, N.J. Thompson and J.K. Tuli. With the exception of the {sup 254}No nuclide, excited-state data for A=254 nuclei are largely unknown. The decay of the 184−μs isomer in {sup 254}No has been studied in two independent experiments, results of which differ significantly, thus precluding adoption of any one particular decay scheme. Only the features that are consistent in these studies are included in the Adopted dataset, whereas independent decay schemes are presented in separate datasets. Information is also presented here for possible production of the {sup 254}U nuclide in a study (1960Di03) of debris of the first large-scale thermonuclear test (Ivy Mike) of November 1, 1952 in the Pacific Ocean.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Mean-field studies of time reversal breaking states in super-heavy nuclei with the Gogny force

Recent progress on the description of time reversal breaking (odd mass and multi-quasiparticle excitation) states in super-heavy nuclei within a mean field framework and using several flavors of the Gogny interaction is reported. The study includes ground and excited states in selected odd mass isotopes of nobelium and mendelevium as well as high K isomeric states in {sup 254}No. These are two and four-quasiparticle excitations that are treated in the same self-consistent HFB plus blocking framework as the odd mass states.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy

Until recently, ground-state nuclear moments of the heaviest nuclei could only be inferred from nuclear spectroscopy, where model assumptions are required. Here, 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. In this work, we reported 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 density distribution in 252,254 No isotopes.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Using isotope shift for testing nuclear theory: The case of nobelium isotopes

We calculate field isotope shifts for nobelium atoms using nuclear charge distributions which come from different nuclear models.We demonstrate that comparing calculated isotope shifts with experiment can serve as a testing ground for nuclear theories. It also provides a way of extracting parameters of nuclear charge distribution beyond nuclear root mean square (rms) radius, e.g., parameter of quadrupole deformation β. The measurements of at least two atomic transitions is needed to disentangle the contributions of the changes in deformation and nuclear rms radius into field isotopic shift. We argue that a previous interpretation of the isotope measurements in terms of δ < r 2 > between 252,254 No isotopes should be amended when nuclear deformation is taken into account. As a result, we calculate isotope shifts for other known isotopes and for hypothetically metastable isotope 286 No for which the predictions of nuclear models differ substantially.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗