Angular momentum limitation of cluster emission from the compound nucleus: 16O(16O, α)28Si and 16O(16O, 8Be)24Mg

doi:10.1016/0370-2693(87)91352-9

Physics Letters B

Volume 199, Issue 2, 17 December 1987, Pages 166-170

https://doi.org/10.1016/0370-2693(87)91352-9 Get rights and content

Abstract

Excitation functions of the (¹⁶O, α) and (¹⁶O, ⁸Be) compound reactions on ¹⁶O have been measured and compared with Hauser-Feshbach model calculations. Using transmission coefficients for penetration of the real potential barrier in the exit channels we find global agreement, in contrast to systematic deviations obtained with optical-model transmission coefficients.

References (25)

M. Blann et al.
Phys. Rev. C
(1981)
M. Blann et al.
Phys. Rev. C
(1982)
C.M. Perey et al.
At. Data Nucl. Data Tables
(1974)
H. Morgenstern
Phys. Rev. Lett.
(1984)
J.M. Blatt et al.
Theoretical nuclear physics
(1952)
W. Hauser et al.
Phys. Rev.
(1952)
R.G. Stokstad
M.A. McMahan et al.
Phys. Rev. C
(1980)
L.C. Vaz et al.
Z. Phys.
(1984)
L.G. Sobotka
Phys. Rev. Lett.
(1983)
L.G. Moretto
Nucl. Phys. A
(1975)
T. Matsuse

G. La Rana

Phys. Rev. C

(1987)

K.G. Bernhardt

Annual Report Beschleunigerlaboratorium München

(1977)

Cited by (6)

Energy levels of light nuclei A = 8,9,10
2004, Nuclear Physics A
Critical angular momentum of cluster evaporation: 16O(16O, α)28Si and 16O(16O, 8Be)24Mg
1992, Nuclear Physics, Section A
Excitation functions of the ¹⁶O+¹⁶O system decaying by α and ⁸Be(g.s.) emission to low-lying states of the respective ²⁸Si and ²⁴Mg residual nuclei have been measured from E_c.m. = 18.35–31.0 MeV. All experimental results are reproduced satisfactorily by Hauser-Feshbach model calculations, if transmission coefficients for potential-barrier penetration are used for all cluster decay channels as well as for the entrance channel. Calculations using optical-model transmission coefficients are systematically at variance with the data, which is explained in terms of exit-channel angular momentum limitation.
Energy levels of A = 21-44 nuclei (VII)
1990, Nuclear Physics, Section A
The experimentally determined properties of A = 21–44 nuclides are complied and evaluated with special emphasis on nuclear spectroscopy.
Separate tables for each of the nuclides reviewed present the available information about the following properties (in this order):
- •
  - excitation energies E_x,
- •
  - γ-ray branching ratios b(γ),
- •
  - γ-ray mixing ratios σ,
- •
  - lifetimes γ_m or widths Λ,
- •
  - neutron, proton, or α-particle resonances,
- •
  - partial widths,
- •
  - single-nucleon transfer reactions,
- •
  - beta-decay,
- •
  - arguments for spin and parity (J^π) and isospin (T) assignments.
For each nuclide a master table summarizing the “best” or adopted values for E_x, J^π; T and τ_m or Λ precedes the auxiliary tables listed above.
The review of each A-chain concludes with a discussion of isospin multiplets.
Figures are presented of the level schemes of all nuclei and, for each A-chain, an overview of the relative energies of the ground states and lowest analogue states of all nuclei in the chain.
Structure phenomena in the orbiting 12c + 24Mg system
1990, Nuclear Physics, Section A
The backward-angle yield from ¹²C + ²⁴Mg has been studied with the technique of inverse kinematics, using ²⁴Mg beams with energies from 90 to 126 MeV. In the different exit channels with 5 ⩽ Z_ejectile ⩽9 the Q-integrated differential cross sections $d σ d θ$ are consistent with isotropy at 130° ⩽ θ_c.m. ⩽ 165°, which is taken as signature of orbiting. The most probable exit energies in the strongly predominant even-Z channels as a function of bombarding energy give evidence for complete damping at angular momenta close to the critical ones for fusion. The results for the weakly populated odd-Z channels suggest that the conditions of damping are affected by the large negative ground-state Q-values.
Structures are observed in the Q-value spectra and in the excitation functions at given Q. The former are identified with high-spin states close to the yrast lines, which are shown to be selectively populated due to the matching conditions for deep-inelastic reactions in light heavy-ion systems. An additional selectivity for natural-parity transitions gives evidence for the conservation of the dinuclear parentage. Narrow fluctuations observed in the excitation functions for fixed narrow Q-windows are attributed to the overlapping of unbound states of the intermediate complex. In the Q-integrated excitation functions these fluctuations cancel, but weak gross structure of a few MeV width remains visible. A statistical analysis of the narrow fluctuations yields coherence widths around 400 keV, corresponding to lifetimes of the intermediate dinucleus around 2 × 10⁻²¹ s.
Spin determination from side-feeding excitation function of the nucleus 128Xe in the 125Te(α, nγ)128Xe and 126Te(α, 2nγ)128Xe reactions
1989, Nuclear Physics, Section A
Selective parity transitions and dinuclear orbiting of C12+ Mg24
1988, Physical Review Letters

^∗: The authors are grateful to G.R. Satchler for providing the numerical values of the double-folding potentials. This work was supported in part by the Polish Ministry of Science and Higher Education under contract CPBP 01.06., by the Bundesministerium für Forschung und Technologie, and by the United States Department of Energy.

¹: On leave from Sektion Physik, Universität München, D-8046 Garching, Fed. Rep. Germany.

²: On leave from Physik Department, Technische Universität München, D-8000 Munich, Fed. Rep. Germany.

View full text

Article preview

Physics Letters B

Abstract

References (25)

Phys. Rev. C

Phys. Rev. C

At. Data Nucl. Data Tables

Phys. Rev. Lett.

Theoretical nuclear physics

Phys. Rev.

Phys. Rev. C

Z. Phys.

Phys. Rev. Lett.

Nucl. Phys. A

Phys. Rev. C

Annual Report Beschleunigerlaboratorium München

Cited by (6)

Energy levels of light nuclei A = 8,9,10

Critical angular momentum of cluster evaporation: <sup>16</sup>O(<sup>16</sup>O, α)<sup>28</sup>Si and <sup>16</sup>O(<sup>16</sup>O, <sup>8</sup>Be)<sup>24</sup>Mg

Energy levels of A = 21-44 nuclei (VII)

Structure phenomena in the orbiting <sup>12</sup>c + <sup>24</sup>Mg system

Spin determination from side-feeding excitation function of the nucleus <sup>128</sup>Xe in the <sup>125</sup>Te(α, nγ)<sup>128</sup>Xe and <sup>126</sup>Te(α, 2nγ)<sup>128</sup>Xe reactions

Selective parity transitions and dinuclear orbiting of C12+ Mg24