Discovery of 11+2 level in 19F

doi:10.1016/0370-2693(69)90212-3

Physics Letters B

Volume 28, Issue 10, 17 March 1969, Pages 653-655

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Abstract

A resonance has been discovered in the $^{15} N (α,γ)^{19} F$ reaction which strongly populates the recently-discovered $[1] 13^{+} 2$ level at 4.648 MeV in ¹⁹F. Measurements show that it corresponds to a level with spin $112$ in ¹⁹F at E_X = 6.500 MeV.

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Cited by (12)

Analogue resonances in 19F
1982, Nuclear Physics, Section A
The reactions ¹⁸O(p, p′γ)¹⁸O, ¹⁸O(p, n′γ)¹⁸F and ¹⁸O(p, α'γ)¹⁵N were observed simultaneously from the yields of 0.937, 1.041,1.080, 1.939, 1.982, 3.921 and 5.270 MeV γ-rays from the decay of excited states of the final nuclei. Excitation functions were measured for proton energies 4.40 to 4.62,4.75 to 4.83 and 5.60 to 5.66 MeV. The yield curves show strong resonances in the inelastic proton channels at E_p = 4.48, 4.58, 4.78 and 5.63 MeV corresponding to ¹⁹F levels at 12.24, 12.33, 12.52 and 13.33 MeV. Spin and parity assignments were made from the γ-ray angular distributions. The 12.33 MeV, 12.52 MeV and 13.33 MeV states in ¹⁹F were assigned $J^{π} = (32^{+}), 52^{(+)} and 32^{−}$ respectively and identified as analogues of 4.998, 5.146 and 5.706 MeV levels of ¹⁹O. A comparison of the excited levels of ¹⁹F is made to levels of ¹⁹O up to an excitation energy of 6.276 MeV.
Levels of 19F from the 15N(α, γ)19F reaction for E<inf>α</inf> = 2.8-4.0 MeV
1977, Nuclear Physics, Section A
Resonances in the ¹⁵N(α, γ)¹⁹F reaction for E_α = 2.8–4.0 MeV have been studied. Resonance strengths and angular distributions have been measured, leading to branching ratios, mixing ratios, γ-decay strengths and spin-parity assignments for the following levels (energies in keV) in $^{19} F : 6281 (52^{+}), 6330 (72^{+}), 6498 (32^{+}), 6526 (32^{+}), 6553 (72), 6592 (92^{+}), 6785 (32^{−}), 6836 (52), 6891 (32^{−}) and 6925 (72^{−})$ .
High spin states in the Kπ = 1 2- band of 19F
1974, Nuclear Physics, Section A
Resonances in the ¹⁵N(α, γ)¹⁹F reaction at E_α = 5413 ± 5 keV and 6258 ± 5 keV corresponding to levels in ¹⁹F at E_x = 8288 ± 2 keV and 8957 ± 2 keV have been studied. Angular distribution and ωγ measurements indicate that the level at 8288 keV has $J^{π} = 132^{−} (92^{−})$ ,while that at 8957 keV has $J^{π} = 112^{+}$ . The values of ωγ are 0.53 ± 0.08 eV and 0.9 ± 0.17 eV respectively. The 8288 keV level decays by a 22.4 ± 3.3 W.u. E2 transition to the $92^{−}$ state at 4032 keV and is suggested to be the $132^{−}$ member of the $K^{π} = 12^{−}$ band.
A study of the 16O(6Li, t)19Ne reaction
1972, Nuclear Physics, Section A
The reaction ¹⁶(⁶Li, t)¹⁹Ne has been employed in the study of ¹⁹Ne with 35 and 36 MeV ⁶Li ions. Triton spectra were obtained covering an excitation energy in ¹⁹Ne up to 10 MeV. Some new strongly excited states were found. Angular distributions were obtained between 6° and 39°, in 3° steps. On the basis of the angular distributions and cross sections the following spin and parity assignments were made: $132^{+}$ , 4.61 MeV; $72^{+}$ , 5.41 MeV; ( $52^{−}, 72^{−}$ and ( $92^{−}, 112^{−}$ , 6.83 MeV, A comparison with the mirror nucleus ¹⁹F is made.
The Jπ = 7+ 2 and 11+ 2, T = 1 2 states of mass 19
1972, Nuclear Physics, Section A
The properties of the $J^{π} = 7^{+} 2 and 11^{+} 2, T = 12$ states of mass 19 are discussed in terms of Coriolis coupling between rotational bands based on the single-particle Nilsson configurations of the N = 2 oscillator shell. Single-nucleon transfer spectroscopic factors are predicted for transitions leading to the positive-parity, $T = 12$ states of mass 19 and are compared with experimental results. It is found that the main feature of these states can be understood using s-d shell configurations.
The weak coupling model applied to the nuclei with A = 16-19. (II). Gamma transitions and spectroscopic factors
1972, Nuclear Physics, Section A
We have formulated particle-hole states according to the weak coupling model where the particle and hole wave functions are respectively eigenfunctions of the particle-particle and hole-hole parts of the Hamiltonian. Previously the energy levels were found to be well given by this model and here we make an extensive comparison between theoretical predictions and experi- mental data on γ-transitions and spectroscopic factors for the nuclei with A = 16–19. Some discrepancies are found, particularly for the 3p-3h states in ¹⁶O, but on the whole the agreement is good and confirms the validity of the weak coupling model.

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^∗: Visiting Scientist, University of Oxford.

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Physics Letters B

Abstract

References (9)

Nucl. Phys.

Bull. Am. Phys. Soc.

Bull. Am. Phys. Soc.

Cited by (12)

Analogue resonances in <sup>19</sup>F

Levels of <sup>19</sup>F from the <sup>15</sup>N(α, γ)<sup>19</sup>F reaction for E<inf>α</inf> = 2.8-4.0 MeV

High spin states in the K<sup>π</sup> = 1 2<sup>-</sup> band of <sup>19</sup>F

A study of the <sup>16</sup>O(<sup>6</sup>Li, t)<sup>19</sup>Ne reaction

The J<sup>π</sup> = 7<sup>+</sup> 2 and 11<sup>+</sup> 2, T = 1 2 states of mass 19

The weak coupling model applied to the nuclei with A = 16-19. (II). Gamma transitions and spectroscopic factors