About the limits of existence of α-cluster structure in nuclei

Spectroscopy of16O using α +12C resonant scattering in inverse kinematics

“…However, a resonance at 15.26 ± 20 MeV has been assigned a spin of 2 + by Frawley et al [23]. This resonance was measured using the 15 N + p entrance channel and has a measured width of 300 ± 100 keV, more than twice that of any state within 500 keV in excitation. It could therefore contribute to this region if it had a significant α-decay width.…”

“…As such, many resonances can be obtained at a single beam energy, without significant loss in the quality of data compared with that of a normal kinematics experiment (as shown in figure 2 and [26]). The method has also been successfully used in the study of cluster states in 18 N using 14 O + 4 He scattering [28]. Here beam energies of 33, 42 and 57 MeV produced well resolved resonances in the excitation energy range of 2-12 MeV.…”

“…Measurements of the ( 6 Li, d) reaction have also been used to study the cluster structure of 16 O using the coincident detection of α-particles resulting from the subsequent α + 12 C break-up of the 16 O. For example, see [14][15][16][17][18][19]. In this instance, resonances in the 16 O excitation energy spectra were populated in the range 10 MeV-35 MeV.…”

Alpha-particle transfer from 6Li to 28Si leading to high excitation of 32S

“…one alpha particle. Energies and spins of highly excited states, as populated by various reactions, have been reported earlier for 16 O and 20 Ne ( [14] and references therein), 24 Mg [15], 28 Si [16] and 32 S ( [3] and references therein).…”

Binary nuclear molecules of an ?-particle and a heavier cluster

“…> The structure is, however, displayed in the e elastic scat-~ 2 2tering [8,9], which exhibits a splitting of the e-cluster states into a fine structure of narrow peaks as seen in ~20 Fig. A -+~ 14 X strong argument for the single a-particle nature of the broadened level is the sum of the reduced a-width of the q2 fine structure levels, because it is of the order of one 10 Wigner limit for single particle states [8]. Angular distributions measured at these peaks in the backward direction have been fitted by squared Le-c 18gendre polynomials, to give the spin of the rotational state c o16 they belong to.…”