Simultaneous ? -ray and electron spectroscopy of Hg 182,184,186 isotopes
Physical Review C
© 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.Background: The mercury isotopes around N=104 are a well-known example of nuclei exhibiting shape coexistence. Mixing of configurations can be studied by measuring the monopole strength ?2(E0), however, currently the experimental information is scarce and lacks precision, especially for the I??I? (I?0) transitions. Purpose: The goals of this study were to increase the precision of the known branching ratios and internal conversion coefficients, to increase the amount of available information regarding excited states in Hg182,184,186, and to interpret the results in the framework of shape coexistence using different models. Method: The low-energy structures in Hg182,184,186 were populated in the ? decay of Tl182,184,186, produced at ISOLDE, CERN and purified by laser ionization and mass separation. The ?-ray and internal conversion electron events were detected by five germanium clover detectors and a segmented silicon detector, respectively, and correlated in time to build decay schemes. Results: In total, 193, 178, and 156 transitions, including 144, 140, and 108 observed for the first time in a ?-decay experiment, were assigned to Hg182,184,186, respectively. Internal conversion coefficients were determined for 23 transitions, out of which 12 had an E0 component. Extracted branching ratios allowed the sign of the interference term in Hg182 as well as ?2(E0;02+?01+) and B(E2;02+?21+) in Hg184 to be determined. By means of electron-electron coincidences, the 03+ state was identified in Hg184. The experimental results were qualitatively reproduced by five theoretical approaches, the interacting boson model with configuration mixing with two differen...