학술논문
In-beam gamma-ray and electron spectroscopy of $^{249,251}$Md
Document Type
Working Paper
Author
Briselet, R.; Theisen, Ch.; Sulignano, B.; Airiau, M.; Auranen, K.; Cox, D. M.; Déchery, F.; Drouart, A.; Favier, Z.; Gall, B.; Goigoux, T.; Grahn, T.; Greenlees, P. T.; Hauschild, K.; Herzan, A.; Herzberg, R. -D.; Jakobsson, U.; Julin, R.; Juutinen, S.; Konki, J.; Leino, M.; Lopez-Martens, A.; Mistry, A.; Nieminen, P.; Pakarinen, J.; Papadakis, P.; Peura, P.; Rahkila, P.; Rey-Herme, E.; Rubert, J.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Scholey, C.; Sorri, J.; Stolze, S.; Uusitalo, J.; Vandebrouck, M.; Ward, A.; Zielińska, M.; Bally, B.; Bender, M.; Ryssens, W.
Source
Phys. Rev. C 102, 014307 (2020)
Subject
Language
Abstract
The odd-$Z$ $^{251}$Md nucleus was studied using combined $\gamma$-ray and conversion-electron in-beam spectroscopy. Besides the previously observed rotational band based on the $[521]1/2^-$ configuration, another rotational structure has been identified using $\gamma$-$\gamma$ coincidences. The use of electron spectroscopy allowed the rotational bands to be observed over a larger rotational frequency range. Using the transition intensities that depend on the gyromagnetic factor, a $[514]7/2^-$ single-particle configuration has been inferred for this band, i.e., the ground-state band. A physical background that dominates the electron spectrum with an intensity of $\simeq$ 60% was well reproduced by simulating a set of unresolved excited bands. Moreover, a detailed analysis of the intensity profile as a function of the angular momentum provided a method for deriving the orbital gyromagnetic factor, namely $g_K = 0.69^{+0.19}_{-0.16}$ for the ground-state band. The odd-$Z$ $^{249}$Md was studied using $\gamma$-ray in-beam spectroscopy. Evidence for octupole correlations resulting from the mixing of the $\Delta l = \Delta j = 3$ $[521]3/2^-$ and $[633]7/2^+$ Nilsson orbitals were found in both $^{249,251}$Md. A surprising similarity of the $^{251}$Md ground-state band transition energies with those of the excited band of $^{255}$Lr has been discussed in terms of identical bands. Skyrme-Hartree-Fock-Bogoliubov calculations were performed to investigate the origin of the similarities between these bands.