530 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
Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions
Instability of the rhodium magnetic moment as origin of the metamagnetic phase transition in alpha-FeRh
Based on ab initio total energy calculations we show that two magnetic states
of rhodium atoms together with competing ferromagnetic and antiferromagnetic
exchange interactions are responsible for a temperature induced metamagnetic
phase transition, which experimentally is observed for stoichiometric
alpha-FeRh. A first-principle spin-based model allows to reproduce this
first-order metamagnetic transition by means of Monte Carlo simulations.
Further inclusion of spacial variation of exchange parameters leads to a
realistic description of the experimental magneto-volume effects in alpha-FeRh.Comment: 10 pages, 13 figures, accepted for publication in Phys. Rev.
Electromagnetic diffraction in optical systems, II. Structure of the image field in an aplanatic system
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