125 research outputs found
Short-lived isomers in Po-192 and Po-194
Isomeric states in Po194 and Po192 were studied at the velocity filter SHIP. The isotopes were produced in the fusion-evaporation reactions Pr141(Fe56, p2n)Po194 and Sm144(V51, p2n)Po192. Several new γ-ray transitions were attributed to the isomers and γ−γ coincidences for both isomers were studied for the first time. The 459-keV transition earlier, tentatively proposed as de-exciting the isomeric level in Po194, was replaced by a new 248-keV transition, and the spin of this isomer was reassigned from (11−) to (10−). The de-excitation of the (11−) isomeric level in Po192 by the 154-keV transition was confirmed and a parallel de-excitation by a 733-keV (E3) transition to (8+) level of the ground-state band was suggested. Moreover, side feeding to the (4+) level of the ground-state band was proposed. The paper also discusses strengths of transitions de-exciting 11− isomers in neighboring Po and Pb isotopes
Loneliness and the Emotional Experience of Absence
In this paper, we develop an analysis of the structure and content of loneliness. We argue that this is an emotion of absence-an affective state in which certain social goods are regarded as out of reach for the subject of experience. By surveying the range of social goods that appear to be missing from the lonely person's perspective, we see what it is that can make this emotional condition so subjectively awful for those who undergo it, including the profound sense of being unable to realise oneself, in collaboration with others
Precision Measurement of the First Ionization Potential of Nobelium
One of the most important atomic properties governing an element’s chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626 21 ± 0.000 05 eV . This work provides a stringent benchmark for state-of-the-art many-body atomic modeling that considers relativistic and quantum electrodynamic effects and paves the way for high-precision measurements of atomic properties of elements only available from heavy-ion accelerator facilities
β-delayed fission and α decay of At196
A nuclear-decay spectroscopy study of the neutron-deficient isotope At196 is reported where an isotopically pure beam was produced using the selective Resonance Ionization Laser Ion Source and On-Line Isotope Mass Separator (CERN). The fine-structure α decay of At196 allowed the low-energy excited states in the daughter nucleus Bi192 to be investigated. A β-delayed fission study of At196 was also performed. A mixture of symmetric and asymmetric fission-fragment mass distributions of the daughter isotope Po196 (populated by β decay of At196) was deduced based on the measured fission-fragment energies. A βDF probability PβDF(At196)=9(1)×10−5 was determined
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