No abstract available

[en] In-beam γ-ray spectroscopic studies of ¹⁸²Hg have revealed five new bands. The 2⁺ state of the prolate band has been identified at an energy of 548.6 keV and is higher than in ¹⁸⁴Hg. A two parameter band mixing calculation results in an interaction energy of 83 keV between the prolate 2⁺ and the oblate 2⁺ states. Several additional new bands are seen including some which are interpreted as quadrupole vibrational bands built on the excited prolate minimum

[en] We reply to the preceding Comment 'Prolate-oblate band mixing'. copyright 1996 The American Physical Society

[en] Shape co-existence refers to the existence of multiple deformations in a single nucleus. It is a well studied phenomenon, both theoretically as well as experimentally. The mass region (A ∼ 200) is a key area where this phenomenon can be observed. A prime example is the ¹⁸⁶Pb nucleus that demonstrates triple shape coexistence. In the neighboring mercury (Hg) isotopes, some work has been done that verifies the presence of multiple deformations. There has been theoretical progress in this particular mass region as well that hints towards existence of the phenomenon in multiple mercury isotopes. Therefore, it can be intuitively understood that the isotopes around A ∼ 200 region with minor variations in neutron and proton numbers could be possible candidates that display shape coexistence. There remains scope to conduct new observations using modern techniques for the study of ^182,184Hg isotopes. These two isotopes lie very close to the magic proton configuration as well as the mid-shell neutron configuration, increasing probability of observing shape coexistence

[en] The energy levels of ¹⁸²Hg have been identified for the first time through comparison of in-beam studies of the reactions ¹⁵⁶¹⁵⁴Gd(³²S,4n)¹⁸⁴¹⁸²Hg. Levels up to 12⁺ in ¹⁸²Hg were established from γ-γ coincidence and singles measurement. The data establish that the ground state shape is near spherical, and that the ground band is crossed by a well deformed band at 4⁺. In contrast to IBA model predictions that the deformed band will rise in energy in ¹⁸²Hg compared to ¹⁸⁴Hg, the energies of the deformed levels in ¹⁸²Hg continue to drop. 7 references

[en] In the neutron-deficient ^182-186Hg isotopes the so-called intruder states come down in excitation energy to the vicinity of the spherical states, yielding the low-lying non-yrast energy levels. The mixing between the states of the coexisting configurations gives rise to transitions with a strong electric monopole component, often referred to as a fingerprint of shape coexistence. Coulomb excitation studies have been performed at the ISOLDE facility on even mass mercury isotopes and reveal the coexistence of the prolate and the weakly-deformed oblate configurations in these nuclei. Recent data from decay spectroscopy at ISOLDE indicates very high internal conversion coefficients (ICC) for the 2⁺ → 2⁺ transitions, suggesting the strong mixing between the 2 shape configurations. These new spectroscopic data (i.e. the ICC and the branching ratios) are used in a re-analysis of the Coulomb excitation yields from REX-ISOLDE, providing a unique opportunity to extract the transitional matrix elements, the spectroscopic quadrupole moments Qs and the electric monopole transition strengths ρ(E0). The new results from the GOSIA calculations for ¹⁸²Hg and ¹⁸⁴Hg will be presented, compared with theory and interpreted in a two-level mixing model. The future Coulomb excitation and decay spectroscopy experiments at ISOLDE will also be discussed. This document is composed of an abstract and the slides of the presentation. (author)

[en] The ${\mathrm{\beta <!--\; ??\; -->}}^{+}$/EC decay of ${}^{182,184}$Tl to excited states in the daughter nuclei ${}^{182,184}$Hg has been investigated at the CERN on-line isotope mass separator facility. In both Tl nuclei two β-decaying states were observed. In the case of ¹⁸⁴Tl, narrow-band laser spectroscopy could be used to disentangle the decay of both isomers. In ¹⁸²Hg a precise energy of 335 (1) keV for the $0_2^{+}$ state was measured together with its feeding from a tentatively proposed $2_3^{+}$ state at 973 keV. Large conversion coefficients for the $2_2^{+}\to <!--\; ???\; -->2_1^{+}$ transition in ${}^{182,184}$Hg were measured to be 7.2 (13) and 14.2 (36), respectively, evidencing a strong E0 component. (paper)

No abstract available

[en] The α decay of mass separated ¹⁹⁰Pb was studied at the UNISOR on-line facility and fine structure was observed, feeding the 2⁺₁ and 0⁺₂ states in ¹⁸⁶Hg identified previously in β-decay and in-beam γ-ray studies. The hindrance factor of the α decay to the excited 0⁺₂ state in ¹⁸⁶Hg is similar to that observed in ^182,184Hg. The variation of the hindrance factor to the 2⁺₁ states in ^182,184,186Hg is discussed. copyright 1996 The American Physical Society

[en] It is demonstrated that the interacting boson model is completely consistent with newly observed energy levels in ¹⁸²Hg. This is accomplished by making a slight change in only one of the parameter values previously used. (orig.)