Isomer studies in the vicinity of the doubly-magic nucleus 100Sn: Observation of a new low-lying isomeric state in 97Ag

• Main Authors: Christine Hornung, Daler Amanbayev, Irene Dedes, Gabriella Kripko-Koncz, Ivan Miskun, Noritaka Shimizu, Samuel Ayet San Andrés, Julian Bergmann, Timo Dickel, Jerzy Dudek, Jens Ebert, Hans Geissel, Magdalena Górska, Hubert Grawe, Florian Greiner, Emma Haettner, Takaharu Otsuka, Wolfgang R. Plaß, Sivaji Purushothaman, Ann-Kathrin Rink, Christoph Scheidenberger, Helmut Weick, Soumya Bagchi, Andrey Blazhev, Olga Charviakova, Dominique Curien, Andrew Finlay, Satbir Kaur, Wayne Lippert, Jan-Hendrik Otto, Zygmunt Patyk, Stephane Pietri, Yoshiki K. Tanaka, Yusuke Tsunoda, John S. Winfield
• Format: Article
• Language: English
• Published: Elsevier 2020-03-01
• Series: Physics Letters B
• Online Access: http://www.sciencedirect.com/science/article/pii/S0370269320300046

Long-lived isomeric states in 97Ag and 101−109In were investigated with the FRS Ion Catcher at GSI. In the isotope 97Ag, a long-lived (1/2−) isomeric state was discovered, and its excitation energy was determined to be 618(38) keV. This is simultaneously the first discovery of a nuclear isomeric state by multiple-reflection time-of-flight mass spectrometry. The measured excitation energies were compared to large-scale shell-model calculations, which indicated the importance of core excitation around 100Sn. Furthermore, advanced mean-field calculations for the 97Ag nucleus and relevant neighboring nuclei were performed, which have contributed to a better understanding of the repetitive appearance of certain isomeric structures in neighboring nuclei, and which have supported the discovery of the isomeric state in 97Ag in a global shell-evolution scheme. Keywords: Mass spectrometry, Multiple-reflection time-of-flight mass spectrometry, Nuclear structure, Isomers, Isomer-to-ground state ratio, Exotic nuclei