αcluster structures in unbound states in¹⁹Ne

Abstract

Abstract. Cluster structures in 19 Ne are studied by the microscopic and macroscopic cluster models. In the microscopic calculation, the coupled-channels problem of ( 3 He+ 16 O) + (α+ 15 O) is solved, and the adiabatic energy surfaces, which are the series of the energy eigenvalues as a function of the He-O distance, are investigated. In the adiabatic energy curves, the several local minima are generated in the spatial region of the small core distance, where the neutron hole inside of the He or O nucleus is strongly coupled to the residual nuclei. The energy spectra, which are constructed from the strong coupling states, nicely reproduce the the low-lying energy levels in the 19 Ne nucleus. In the macroscopic approach, the α + 15 O potential is evaluated from the elastic scattering of the α + 15 N system, and the resonant levels of the α + 15 O system are calculated under the absorbing boundary condition. The potential model predicts the existence of the resonances above the α threshold, which has a weak-coupling scheme of the α particle and one hole inside of the 16 O nucleus. The extended microscopic calculations of ( 3 He+ 16 O) + (α+ 15 O) + ( 5 He+ 14 O) are performed in order to see the coupling effect of the 5p-2h configuration, which corresponds to the shell model limit of the 5 He + 14 O cluster configuration. The extended calculation suggests that the 5 He + 14 O configuration plays an important role on the formation of the 3/2 + resonance at 0.5 MeV with respect to the α threshold. IntroductionThe α cluster structures have been extensively studied for the so-called 4N nuclei with N = Z, such as 8 Be = 2α, 12 C = 3α, 16 On the contrary, cluster structures in the 4N systems with a hole in a cluster core, are also interesting research subjects [7][8][9][10][11]. For example, there is a recent study of 11 B = α + α + t, corresponding to a proton hole system of 12 C = 3α [7]. Pioneering work of the hole system is the study of the 19 F nucleus [8][9][10][11]. The 19 F nucleus is the one proton deficient system of 20 Ne, and the rotational bands a

New measurement of 4He and proton decays from resonant states in 19Ne*

“…a Calculated from and results obtained in Reference [16] b Reference [11] c Reference [14] d Reference [15] e Reference [36] f Reference [10] g Reference [34] h Reference [16] New measurement of 4 He and proton decays from resonant states in 19 1 and [15]). Among them, the ratios of the decay widths were calculated as 1.754 (14) and 15.2 (1.2) for two close states at 7.879 (26) and 8.072 (30) MeV, respectively, corresponding to the 7.863 (39) and 7.974 (10) MeV states, respectively, measured by Dalouzy (Table 1 and [14]), respectively.…”

Microscopic Coupled-channels Study Of The Alpha Cluster Structures In 19Ne

“…(2.5) for the coupled channels of ( 3 He+ 16 O) + (α+ 15 O) and calculate the adiabatic energy surfaces (AESs). In the AESs, the structure change from the two-body weak-coupling states to the one-body strong-coupling states occurs as the distance parameter S gets smaller [13]. The boundary of the weak and strong coupling states is S = 6.5 fm, and we call this boundary distance S C .…”