Systematic study of the mixed ground-state and “intruder” bands in 110, 112, 114Cd

Délèze, M.; Drissi, S.; Kern, J.; Tercier, Pierre-Alain; Vorlet, J.P.; Říkovská, J.; Otsuka, Takaharu; Judge, Steven; Williams, A. P.

doi:10.1016/0375-9474(93)90482-d

Cited by 103 publications

(55 citation statements)

References 31 publications

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“…In the following sections, members of the intruder band are labeled with (i) to facilitate the discussion. [6,9,10] between the intruder states, described as having predominately an O (6) character, and vibrational states, possessing predominately U(5) character, in an interacting boson model-2 (IBM-2) formalism. Results from this calculation for 110 Cd, using the parameters of Refs.…”

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confidence: 99%

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Detailed spectroscopy of110Cd: Evidence for weak mixing and the emergence ofγ-soft behavior

Garrett¹,

Bangay²,

Varela³

et al. 2012

Phys. Rev. C

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A study of the β + /EC decay of 110 In into levels of 110 Cd is combined with a reanalysis of data from a previous study of 110 Cd with the (n, n ′ γ) reaction with monoenergetic neutrons. The γγ coincidences from the 110 In decay leads to many new assignments of γ rays observed in the (n, n ′ γ) reaction, permitting the observation of weak low-energy transitions, and setting stringent upper limits on unobserved decay branches. The uncertainties on many of the lifetimes from the (n, n ′ γ) reaction are significantly reduced, and limits are established for the lifetimes of levels too long for a direct measurement. The absence of enhanced transitions between the previously assigned phonon states and the deformed intruder states strongly suggests that mixing between the configurations is generally weak, refuting the strong-mixing scenario as an explanation of the decay pattern of the excited 0 + states in 110 Cd. The decay pattern of the non-intruder states is suggestive of a γ-soft rotor, or O(6) nucleus, rather than a vibrational, or U (5) pattern. The existence of a 4p − 6h proton excitation in 110 Cd is also suggested.

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confidence: 99%

“…Results from this calculation for 110 Cd, using the parameters of Refs. [9,11], are shown for selected transitions in Table I alongside calculations with no mixing between the intruder and non-intruder states and data for 110,112 Cd. These calculations are generic for all the Cd isotopes.…”

mentioning

confidence: 99%

Detailed spectroscopy of110Cd: Evidence for weak mixing and the emergence ofγ-soft behavior

Garrett¹,

Bangay²,

Varela³

et al. 2012

Phys. Rev. C

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“…Soon thereafter, measurements [9,10] on 110 Cd were also viewed as being in good agreement with the vibrational model. However, a study [12] of 116 Cd found that the decays of the 0 + 2 and 0 + 3 states could not be explained in the usual strong-mixing scenario [4,11]; the decay of the intruder band head (the 0 + 3 state in 116 Cd) remained enhanced over the decay of the 0 + "two-phonon" state, despite the latter being lower in energy. A re-examination of the (n, n γ) results for 112 Cd with a more extensive analysis found serious discrepancies between the experimental data and IBM-2 calculations for the three-phonon levels [13], as did a study of 114 Cd [14].…”

Section: Complementarity In Electromagnetic Matrix Elementsmentioning

confidence: 98%

Complementarity in nuclear structure studies

Garrett

2015

EPJ Web of Conferences

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Abstract. The nuclear many-body system displays a wide variety of behaviors, including collective and singleparticle degrees of freedom. Specific reactions may probe these different aspects, the data from which may both complement and also appear to be in conflict with each other. In the present work, examples are given where information from one experiment enhances and reinforces the information from another, and also an example where the data appear to be in conflict and result in a re-interpretation of structure.

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“…The best agreement with the data assumed a highly anharmonic multiphonon structure requiring the shifting of some of the three-phonon states into the region of the two phonon states. Detailed spectroscopy of the Cd isotopes by the Fribourg [18][19][20] and Jyväskylä [21] groups reinforced the existence of the intruder bands, but came to different conclusions…”

Section: Questioning CD As a Vibrational Paradigmmentioning

confidence: 99%

The evolving structure of the Cd isotopes

Garrett

2014

EPJ Web of Conferences

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Abstract. The even-even Cd isotopes have long been cited as one of the prime examples of vibrational behaviour, identified soon after the Bohr model was developed in the early 1950's. By the late 1970's, the presence of intruder states and shape coexistence were identified, but the underlying vibrational nature remained intact. More recently, the robustness of the multiphonon states was questioned, prompting detailed spectroscopic investigations at a number of facilities, including the use of the (n, n ′ γ) reaction and β-decay studies with modern γ-ray spectrometers. Combining results from these studies, a re-examination of the structure of the mid-shell Cd isotopes suggests that they may represent deformed γ-soft rotors rather than spherical vibrators. The early years: Cd as spherical vibratorsThe collective model of Bohr and Mottelson [1,2], developed in the early 1950's, is one of the foundational models of nuclear structure. Its three main paradigms, deformed-rotational, spherical vibrational, and γ-soft, remain to this day benchmarks against which structure of nuclei are compared. Soon after the development of the vibrational limit of the Bohr Hamiltonian, in 1955 Scharff-Goldhaber and Weneser [3] used the ratio of the energy of the second excited state to the first excited state, E 2 /E 1 , to identify candidates for spherical vibrators. In this early work, the Cd nuclei 110 Cd and 114 Cd were cited as candidates, having E 2 /E 1 ≈ 2. Soon thereafter, in 1956 [4], spectroscopy following the (n, γ) capture reaction identified an additional 2 + level in the vicinity of the two-phonon triplet in 114 Cd. This was seen as a problem for the vibrational model by Cohen and Price [5], who, in 1960, using the (d, p) reaction, not only confirmed the additional 2 + level in 114 Cd, but also found an extra 0 + state. Further, they identified two 0 + and two 2 + states in 112 Cd at twice the energy of the 2 + 1 state. The validity of the phonon model was supported, however, by a series of Coulomb excitation experiments by McGowan and co-workers [6], results of which are shown in Fig. 1, that determined in 112,114,116 Cd the ratio B(E2; 4 + 1 → 2 + 1 )/B(E2; 2 + 1 → 0 + 1 ) was approximately equal to 2 (within the experimental uncertainty). Only in 110 Cd did the ratio of 1.42 ± 0.19 deviate significantly from 2.0. Furthermore, in 114,116 Cd, the ratio B(E2; 0 ′+ → 2 + 1 )/B(E2; 2 + 1 → 0 + 1 ) was measured to be near unity, again providing support to the phonon model.

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Systematic study of the mixed ground-state and “intruder” bands in 110, 112, 114Cd

Cited by 103 publications

References 31 publications

Detailed spectroscopy of110Cd: Evidence for weak mixing and the emergence ofγ-soft behavior

Detailed spectroscopy of110Cd: Evidence for weak mixing and the emergence ofγ-soft behavior

Complementarity in nuclear structure studies

The evolving structure of the Cd isotopes

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