Decay spectroscopy of the odd-proton nuclei
249
Md and
251
Md has been performed. High-
K
isomeric states were identified for the first time in these two nuclei through the measurement of their ...electromagnetic decay. An isomeric state with a half-life of 2.8(5) ms and an excitation energy
≥
910
keV was found in
249
Md. In
251
Md, an isomeric state with a half-life of 1.4(3) s and an excitation energy
≥
844
keV was found. Similarly to the neighbouring
255
Lr, these two isomeric states are interpreted as 3 quasi-particle high-
K
states and compared to new theoretical calculations. Excited nuclear configurations were calculated within two scenarios: via blocking nuclear states located in proximity to the Fermi surface or/and using the quasiparticle Bardeen–Cooper–Schrieffer method. Relevant states were selected on the basis of the microscopic-macroscopic model with a deformed Woods–Saxon potential. The most probable candidates for the configurations of
K
-isomeric states in Md nuclei are proposed.
In the study of the odd-\(Z\), even-\(N\) nuclei \(^{243}\)Es and \(^{249}\)Md, performed at the University of Jyv\"askyl\"a, the fusion-evaporation reactions ...\(^{197}\)Au(\(^{48}\)Ca,2\(n\))\(^{243}\)Es and \(^{203}\)Tl(\(^{48}\)Ca,2\(n\))\(^{249}\)Md have been used for the first time. Fusion-evaporation residues were selected and detected using the RITU gas-filled separator coupled with the focal-plane spectrometer GREAT. For \(^{243}\)Es, the recoil decay correlation analysis yielded a half-life of \(24 \pm 3\)s, and a maximum production cross section of \(37 \pm 10\) nb. In the same way, a half-life of \(26 \pm 1\) s, an \(\alpha\) branching ratio of 75 \(\pm\) 5%, and a maximum production cross section of 300 \(\pm\) 80 nb were determined for \(^{249}\)Md. The decay properties of \(^{245}\)Es, the daughter of \(^{249}\)Md, were also measured: an \(\alpha\) branching ratio of 54 \(\pm\) 7% and a half-life of 65 \(\pm\) 6 s. Experimental cross sections were compared to the results of calculations performed using the KEWPIE2 statistical fusion-evaporation code.
Decay spectroscopy of the odd-proton nuclei $^{249}$Md and $^{251}$Md has
been performed. High-$K$ isomeric states were identified for the first time in
these two nuclei through the measurement of ...their electromagnetic decay. An
isomeric state with a half-life of $2.8(5)$ ms and an excitation energy $\geq
910$ keV was found in $^{249}$Md. In $^{251}$Md, an isomeric state with a
half-life of $1.4(3)$ s and an excitation energy $\geq 844$ keV was found.
Similarly to the neighbouring $^{255}$Lr, these two isomeric states are
interpreted as 3 quasi-particle high-$K$ states and compared to new theoretical
calculations. Excited nuclear configurations were calculated within two
scenarios: via blocking nuclear states located in proximity to the Fermi
surface or/and using the quasiparticle Bardeen-Cooper-Schrieffer method.
Relevant states were selected on the basis of the microscopic-macroscopic model
with a deformed Woods-Saxon potential. The most probable candidates for the
configurations of $K$-isomeric states in Md nuclei are proposed.
Decay spectroscopy of the odd-proton nuclei \(^{249}\)Md and \(^{251}\)Md has been performed. High-\(K\) isomeric states were identified for the first time in these two nuclei through the measurement ...of their electromagnetic decay. An isomeric state with a half-life of \(2.8(5)\) ms and an excitation energy \(\geq 910\) keV was found in \(^{249}\)Md. In \(^{251}\)Md, an isomeric state with a half-life of \(1.4(3)\) s and an excitation energy \(\geq 844\) keV was found. Similarly to the neighbouring \(^{255}\)Lr, these two isomeric states are interpreted as 3 quasi-particle high-\(K\) states and compared to new theoretical calculations. Excited nuclear configurations were calculated within two scenarios: via blocking nuclear states located in proximity to the Fermi surface or/and using the quasiparticle Bardeen-Cooper-Schrieffer method. Relevant states were selected on the basis of the microscopic-macroscopic model with a deformed Woods-Saxon potential. The most probable candidates for the configurations of \(K\)-isomeric states in Md nuclei are proposed.
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