Dimers based on the α + α potential and chain states of carbon isotopes

Oertzen, W. von

doi:10.1007/s002180050255

Cited by 201 publications

(244 citation statements)

References 25 publications

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“…In such cases, nucleons exchanged between different α clusters ensure the binding of the system. The existence of these structures was shown in 9 Be through the identification of rotational bands built on the deformed molecular α:n:α state [67,68]. An analogue identification of states in 10 Be has been more elusive.…”

Section: Cluster Statesmentioning

confidence: 99%

Radioactive ion beam physics at the cyclotron research centre Louvain-la-Neuve

Huyse¹,

Raabe²

2011

J. Phys. G: Nucl. Part. Phys.

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Abstract.The first beam of post-accelerated radioactive ions was realized in 1989 at the Louvainla-Neuve research facility. The method employed two coupled cyclotrons to produce, separate and re-accelerate the species of interest. Several technological challenges were solved in the process, to obtain pure and intense beams for use in nuclear physics research. Similarly, new techniques were developed and refined for the measurement of the nuclear reactions induced by the radioactive beams. The available energy range made the facility particularly suited for nuclear astrophysics studies, and important results were obtained in the determination of stellar reaction rates using beams of 7 Be, 13 N, 18 F, 18,19 Ne. A beam of 6 He ions was extensively used in studies of the nuclear structure (halos, molecular states) and dynamics (the reaction process at energies around the potential barrier).

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Section: Cluster Statesmentioning

confidence: 99%

Radioactive ion beam physics at the cyclotron research centre Louvain-la-Neuve

Huyse¹,

Raabe²

2011

J. Phys. G: Nucl. Part. Phys.

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“…The moment of inertia is almost the same as the negative-parity band; however, further investigation (e.g., explicitly imposing the resonance condition) is needed, since the resonance energy is high. Experimentally, these are two parity split bands with K = 3/2, corresponding to an intrinsic 9 Be + α structure. The single-particle orbit of neutrons for these doublet bands is discussed in Ref.…”

mentioning

confidence: 97%

“…For instance, the presence of rotational bands with the α-α structure in the excited states of 10 Be and 12 Be and the breaking of the magic number (N = 8) due to the clustering of the core have attracted much attention [9][10][11][12][13][14][15][16]. We have suggested, based on the molecular-orbit model, that these phenomena can be well explained by introducing single-particle orbits around the α-α cluster structure [15].…”

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confidence: 99%

Linear-chain structure of three α clusters inC13

2006

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We investigate a linear-chain configuration of three α clusters with a neutron in 13 C. To characterize this configuration, an operator P is introduced, which is the sum of parity inversion operators for each proton. The states with positive expectation values for this operator are found to form a rotational band structure, and the moment of inertia agrees well with the experimentally suggested value. Allowing a small bending angle stabilizes the linear-chain configuration of three α clusters with a valence neutron, which is a hyper-deformed state. The realization of linear-chain configurations has been a long-standing objective of nuclear structure physics. However, it is difficult to stabilize this configuration in nuclear systems, which is contrary to the case in atomic systems. The linearchain structure of three α clusters was suggested nearly half a century ago [1], and the second 0 + (0 + 2 ) state of 12 C at E x = 7.65 MeV just above the three α threshold energy is a candidate for having this structure. This state is considered to have an exotic cluster structure that is analogous with the so-called mysterious 0 + state of 16 O at E x = 6.06 MeV, which has a 12 C+α cluster structure and is not completely explained by a simple shell-model picture. However, the 0 + 2 state, which plays a crucial role in the synthesis of 12 C from three 4 He nuclei in stars [2], has been proven to contain not only the linear-chain configuration but also various three α configurations by many microscopic cluster models [3]. The state is gaslike without a specific geometric shape, and it has been recently reinterpreted as an α-condensed state [4]. The search for linear-chain states of α clusters has been extended to heavier N = Z nuclei [5][6][7][8]; however, further investigations are needed to confirm that those states are really linear-chain structures.The difficulty of the linear-chain configuration is briefly explained in the following way. From the harmonic-oscillator point of view, if three α clusters form a linear configuration on the z axis, four nucleons in the central α cluster occupy the lowest s orbits; however, eight nucleons in the other α clusters are excited to higher orbits such as the p(z) and sd(z 2 ) orbits due to the antisymmetrization effect. If the system has some bending angle, three α clusters form a two-dimensional configuration in the xz plane, and in this case four nucleons corresponding to the sd(z 2 ) orbits are deexcited to the p(x) orbits. We may conclude that in light nuclei, where the value ofhω is about 20 MeV, it is difficult to prevent the mixing of states with different bending angles.Another difficulty comes from the weak-coupling nature of the nuclear systems. If the state is largely clusterized, i.e., not only the total system of three α clusters, the α-α subsystem ( 8 Be) tends to have good angular momentum, since the angular momentum projection for the intrinsic wave function of 8 Be to the 0 + state induces a decrease in the energy by about 10 MeV.This angular momentum projection of...

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“…However, it has been a long-standing dream of nuclear structure physicists to find an equilateral-triangular shape. While various cluster structures with different shapes have been considered in light exotic nuclei [1][2][3][4][5], the triangular shape still remains beyond the explored frontiers.…”

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confidence: 99%

Equilateral-Triangular Shape inC14

et al. 2004

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An equilateral-triangular shape of three clusters surrounded by excess neutrons is suggested for 14 C, based on the molecular-orbit model. It is found that the attractive interaction between an excess neutron and an particle stabilizes the K 0 and 3 ÿ rotational bands, which demonstrates an equilateral-triangular symmetry. This K 3 ÿ band at 3 MeV below the 10 Be threshold energy corresponds to the experimentally observed band built on top of the second 3 ÿ state. A positive-parity rotational band (0 , 2 , 4 ) arises similarly. These two bands suggest a molecular 3-structure stabilized by the excess neutrons and can be viewed as a realization of the crystallization in the dilute nuclear medium.

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Dimers based on the α + α potential and chain states of carbon isotopes

Cited by 201 publications

References 25 publications

Radioactive ion beam physics at the cyclotron research centre Louvain-la-Neuve

Radioactive ion beam physics at the cyclotron research centre Louvain-la-Neuve

Linear-chain structure of three α clusters inC13

Equilateral-Triangular Shape inC14

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