THE 6He+6He AND α+8He CLUSTER STATES IN 12Be VIA α-INELASTIC SCATTERING

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1858-1861 ◽  
Author(s):  
A. SAITO ◽  
S. SHIMOURA ◽  
T. MINEMURA ◽  
Y. U. MATSUYAMA ◽  
H. BABA ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Inelastic Scattering ◽  
Excited States ◽  
Rotational Band ◽  
Cluster Structure ◽  
Decomposition Analysis ◽  
Incident Beam ◽  
Negative Parity ◽  
Angular Correlations ◽  
Measured Momentum

Cluster structures in the neutron-rich nucleus 12 Be were experimentally investigated via α-inelastic scattering. Excited states in the 12 Be nucleus were populated by a 12 Be (αα') reaction at 60 A MeV in the inverse kinematics, and identified by measuring a 6 He +6 He and α+8 He breakup channels in coincidence. The differential cross section and the angular correlations between the decay particles were obtained for each excitation energy at 10–20 MeV for 6 He +6 He and at 9–19 MeV for α+8 He , respectively, reconstructed by the measured momentum vectors of the two helium isotopes. A multipole decomposition analysis based on the distorted-wave Born approximation was applied for the angular distribution of the inelastic scattering together with the angular correlation between the decay particles with respect to the directions of the incident beam and to the momentum transfer simultaneously. From the decomposed excitation energy spectra for J=0-4, several new excited states were identified. The 0+ excited states were candidates of the band-head of a largely deformed rotational band. The 11.3-MeV 0+ state was found to decay only into the 6 He +6 He channel. This result support the recent theoretical result by the generalized two-center cluster model. Several negative-parity excited states were observed in the α+8 He channel. These excited states possibly forming a negative-parity rotational band, which is very closed to the positive-parity band, can be connected to the existence of the extremely developed cluster structure in 12 Be .

NEW 5− AND 6+ STATES IN Ne20

1964 ◽  
Vol 42 (3) ◽  
pp. 477-488 ◽  
Author(s):  
J. A. Kuehner ◽  
J. D. Pearson
Keyword(s):  
Excited States ◽  
Rotational Band ◽  
Ground State ◽  
Negative Parity ◽  
Alpha Particles ◽  
Excitation Energies ◽  
Angular Correlations ◽  
Fourth Member

Excited states of Ne20 at excitation energies of 8.46 Mev and 8.79 Mev have been identified and assigned spin and parity values of 5− and 6+, respectively. The excited states were produced in the C12(C12, α)Ne10 reaction and the spin assignments were made on the basis of angular correlations of the decay alpha particles from these states leaving O16 in its ground state. It is postulated that the 5− state is the fourth member of a K = 2 negative-parity rotational band based on the 2– 4.97-Mev state and that the 6+ state is the fourth member of a K = 0 rotational band based on the 0+ ground state of Ne20.

SYSTEMATIC STUDY OF THE MANY-PARTICLE AND MANY-HOLE STATES IN AND AROUND THE ISLAND OF INVERSION

2011 ◽  
Vol 20 (04) ◽  
pp. 893-896 ◽  
Author(s):  
MASAAKI KIMURA
Keyword(s):  
Molecular Dynamics ◽  
Excitation Energy ◽  
Excited States ◽  
Systematic Study ◽  
Ground State ◽  
Negative Parity ◽  
Parity Assignment ◽  
Island Of Inversion ◽  
The Many

Deformation and many particle and many hole configurations in the island of inversion are investigated with Antisymmetrized Molecular Dynamics (AMD). The result suggests the coexistence of many particle and many hole configurations with different deformation at small excitation energy. In the case of 33 Mg , we suggest the negative-parity assignment for the ground state. Other particle hole configurations are predicted as the excited states.

Modification of HAM/3 excitation energies for ΠΠ* transitions of linear molecules

1980 ◽  
Vol 58 (16) ◽  
pp. 1687-1690 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Excitation Energy ◽  
Explicit Expression ◽  
Excited States ◽  
Configuration Interaction ◽  
Excitation Energies ◽  
Carbon Suboxide ◽  
Numerical Examples ◽  
Energy Correction ◽  
Linear Molecules ◽  
Configuration Interaction Calculations

The excitation energies calculated by the HAM/3 procedure for ΠΠ* transitions in linear molecules can be internally inconsistent by as much as ± 0.6 eV. In the recent study by Åsbrink etal., the problem was avoided by adopting Recknagel's expressions and requiring the proper average ΠΠ* excitation energy. In this paper, we trace the small inconsistency back to its origin in HAM/3 theory and derive the analytical expression for the energy correction as well as Recknagel's formulas. Numerical examples studied include all seven linear molecules investigated by Åsbrink etal. The explicit expression for the correction enables us to perform meaningful configuration-interaction calculations on the excited states, as illustrated by the carbon suboxide molecule.

Gamma-Ray Angular Correlations and Lifetime Measurements for Some Excited States ofNe21

1969 ◽  
Vol 186 (4) ◽  
pp. 1174-1188 ◽  
Author(s):  
J. G. Pronko ◽  
C. Rolfs ◽  
H. J. Maier
Keyword(s):  
Excited States ◽  
Gamma Ray ◽  
Lifetime Measurements ◽  
Angular Correlations

Elastic and inelastic scattering in the 6Li, 9Be + 12C systems: excitation of unbound excited states and cluster transfers

1995 ◽  
Vol 591 (2) ◽  
pp. 349-370 ◽  
Author(s):  
J. Carter ◽  
Z.Z. Vilakazi ◽  
R.W. Fearick ◽  
V. Hnizdo ◽  
E. Muskat ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Excited States ◽  
Elastic And Inelastic Scattering

Search for cluster structure of excited states in 14 C

2004 ◽  
Vol 21 (2) ◽  
pp. 193-215 ◽  
Author(s):  
W. von Oertzen ◽  
H. G. Bohlen ◽  
M. Milin ◽  
Tz Kokalova ◽  
S. Thummerer ◽  
...  
Keyword(s):  
Excited States ◽  
Cluster Structure

Inference on fission timescale from neutron multiplicity measurement in18O+184W

2022 ◽  
Author(s):  
Niraj Kumar Rai ◽  
Aman Gandhi ◽  
M T Senthil Kannan ◽  
Sujan Kumar Roy ◽  
Saneesh Nedumbally ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Beam Energy ◽  
Incident Beam ◽  
Fission Process ◽  
Incident Beam Energy ◽  
Neutron Evaporation ◽  
Neutron Multiplicities ◽  
Nuclear Dissipation ◽  
Fission Yields ◽  
Primary Compound

Abstract The pre-scission and post-scission neutron multiplicities are measured for the 18O + 184W reaction in the excitation energy range of 67.23−76.37 MeV. Langevin dynamical calculations are performed to infer the energy dependence of fission decay time in compliance with the measured neutron multiplicities. Different models for nuclear dissipation are employed for this purpose. Fission process is usually expected to be faster at a higher beam energy. However, we found an enhancement in the average fission time as the incident beam energy increases. It happens because a higher excitation energy helps more neutrons to evaporate that eventually stabilizes the system against fission. The competition between fission and neutron evaporation delicately depends on the available excitation energy and it is explained here with the help of the partial fission yields contributed by the different isotopes of the primary compound nucleus.

Simulation of the Inelastic Alpha-Particle Scattering Reaction for Investigating the Cluster Structure of Excited States of 9Be

2019 ◽  
Vol 50 (5) ◽  
pp. 605-607
Author(s):  
A. A. Kasparov ◽  
E. S. Konobeevski ◽  
S. V. Zuyev ◽  
M. V. Morodvskoy ◽  
A. A. Afonin ◽  
...  
Keyword(s):  
Excited States ◽  
Alpha Particle ◽  
Cluster Structure ◽  
Particle Scattering

Three-center cluster states in 11C and 11B

2006 ◽  
Vol 21 (31n33) ◽  
pp. 2403-2409
Author(s):  
Yoshiko Kanada-En'yo
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Excited States ◽  
Cluster State ◽  
Cluster Structure ◽  
Cluster States ◽  
Spin Parity ◽  
Variational Calculations

Structures of excited states in 11 C and 11 B were studied based on variational calculations after spin-parity projection in a framework of antisymmetrized molecular dynamics (AMD). The calculations systematically reproduce experimental data of the transition strengths such as Gamov-Teller(GT) and M1 transitions. A well-developed cluster structure of 2α+3 He (t) was found in the [Formula: see text] state of 11 C (11 B ). We assigned this state to the observed [Formula: see text] state at 8 MeV. The calculations reproduce the small [Formula: see text] which has been measured in the recent experiments. It was found that the [Formula: see text] state has a dilute cluster state, and its features are similar to those of the [Formula: see text] which is considered to be a gas state of three α clusters.

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