https://doi.org/10.1140/epja/s10050-021-00631-4
Regular Article - Experimental Physics
First observation of high-K isomeric states in
Md and
Md
1
Irfu, CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
2
Department of Physics, University of Jyvaskyla, P.O. Box 35, 40014, Jyvaskyla, Finland
3
Department of Physics, Oliver Lodge Laboratory, University of Liverpool, L69 7ZE, Liverpool, UK
4
Institut Pluridisciplinaire Hubert Curien, 67037, Strasbourg, France
5
IJCLab, IN2P3-CNRS, Orsay Campus, 91405, Orsay, France
6
Institute of Physics, Slovak Academy of Sciences, 84511, Bratislava, Slovakia
7
Institute of Physics, University of Zielona Góra, Z. Szafrana 4a, 65-516, Zielona Gora, Poland
8
National Centre for Nuclear Research, Pasteura 7, 02-093, Warsaw, Poland
9
Radiation and Nuclear Safety Authority-STUK, Laippatie 4, 00880, Helsinki, Finland
10
University of Lund, Box 118, 221 00, Lund, Sweden
11
Laboratory of Radiochemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki, Finland
12
CERN, 1211, Geneva 23, Switzerland
13
GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291, Darmstadt, Germany
14
Fortum, Power Division, P.O. Box 100, 00048, Fortum, Finland
15
STFC Daresbury Laboratory, Daresbury, WA4 4AD, Warrington, UK
16
International Atomic Energy Agency, Vienna, Austria
17
Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, 60439, Lemont, IL, USA
Received:
2
July
2021
Accepted:
14
November
2021
Published online:
1
December
2021
Decay spectroscopy of the odd-proton nuclei Md and
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
keV was found in
Md. In
Md, an isomeric state with a half-life of 1.4(3) s and an excitation energy
keV was found. Similarly to the neighbouring
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.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021