Systematic study of low-spin states in even Cd nuclei

Kumpulainen, J.; Julin, R.; Kantele, J.; Passoja, A.; Trzaska, W. H.; Verho, E.; Väärämäki, J.; Cutoiu, D.; Ivaşcu, M.

doi:10.1103/physrevc.45.640

Cited by 82 publications

(20 citation statements)

References 48 publications

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“…Comprehensive level schemes have become available for the many of the stable Cd isotopes through detailed spectroscopy, by using primarily fusion-evaporation reactions [11][12][13][14][15][16][17], inelastic scattering and transfer reactions [8,[18][19][20][21][22][23][24], the (n, n γ ) reaction [9,12,[25][26][27][28][29][30][31][32], and β decay [12][13][14][33][34][35]. These studies have provided a wealth of data not previously available.…”

Section: Introductionmentioning

confidence: 99%

Breakdown of vibrational motion in the isotopesCd110−116

2008

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A systematic study is made of the Cd isotopes [110][111][112][113][114][115][116] Cd by making use of available experimental data and interacting boson model calculations incorporating both normal vibrational levels and intruder excitations. At the two-phonon level, the calculations appear to reproduce the data reasonably well in 110-114 Cd, whereas they break down completely for the 0 + states in 116 Cd. At the three-phonon level, systematic deviations occur across the Cd isotopic chain, revealing the breakdown of vibrational motion in low-spin states. Combined with the failure to reproduce 116 Cd at the two-phonon level, it is possible that the Cd isotopes may not represent vibrational systems and that the essential physics of their motion has been missing.

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Section: Introductionmentioning

confidence: 99%

Breakdown of vibrational motion in the isotopesCd110−116

2008

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“…Kawase et al in 1972 [9] first proposed a doublet of levels with spins 0 + and 3 − at 2079 keV. This was later confirmed [1][2][3]. An upper limit was determined by Corminboeuf et al, Ref [4], for the 1421.1-keV transition from the 2078.6-keV 0 + level.…”

Section: Resultsmentioning

confidence: 72%

“…Experiments with the (α, 2n) reaction by Kern et al [1], β decay measurements by Bertschy et al [2], light-ion induced reactions and decays by Kumpulainen et al [3], and an (n, n ′ γ) study by Corminboeuf et al [4] have identified multi-phonon states in the 110 Cd decay scheme indicating vibrational motion. The Cd nuclei have been considered as some of the best examples of near-harmonic vibrational behavior [5].…”

Section: Introductionmentioning

confidence: 99%

High-Statistics Study of theβ⁺/EC-Decay of¹¹⁰In

Varela

Garrett

Ball

et al. 2014

EPJ Web of Conferences

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Abstract.A study of the 110 In β + /EC decay was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) facility to probe the nuclear structure of 110 Cd. The data were collected in scaled-down γ-ray singles, γ − γ coincidence, and γ-electron coincidence mode. The data were sorted and a random-background subtracted γ − γ matrix was created containing a total of 850 million events. We expanded the level scheme of 110 Cd significantly by identifying 75 levels under 3.8 MeV, including 12 new ones, and increased the number of previously observed transitions from these levels to 273. The γ-ray branching intensities have been extracted through an analysis of the coincidence intensities. The branching ratios were combined with a reanalysis of lifetimes measurements obtained in an (n, n ′ γ) reaction with monoenergetic neutrons for the calculation of B(E2) values and these results have lead to the proposal of a γ-soft rotor, or O(6) nucleus, rather than a vibrational, or U(5) pattern for the nature of the low-lying, low-spin levels in 110 Cd.

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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 low-spin states in even Cd nuclei

Cited by 82 publications

References 48 publications

Breakdown of vibrational motion in the isotopesCd110−116

Breakdown of vibrational motion in the isotopesCd110−116

High-Statistics Study of theβ⁺/EC-Decay of¹¹⁰In

The evolving structure of the Cd isotopes

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Systematic study of low-spin states in even Cd nuclei

Cited by 82 publications

References 48 publications

Breakdown of vibrational motion in the isotopesCd110−116

Breakdown of vibrational motion in the isotopesCd110−116

High-Statistics Study of theβ+/EC-Decay of110In

The evolving structure of the Cd isotopes

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High-Statistics Study of theβ⁺/EC-Decay of¹¹⁰In