Using the total-Routhian-surface （TRS） method, the rotational behaviors of fission isomers in the second well of actinide nuclei 234-242U, 236-244pu and 238-246Cm were investigated. The pairing-deformation-frequency self-consistent TRS calculations repro- duced reasonably the experimental moments of inertia extracted from spectroscopic data. It is calculated that, in these largely elongated （β2 ≈0.65 and β4≈ 0.03） fission isomers, the ν1/2-[981] neutron and π1/2＋[651] proton align simultaneously at rotational frequency hω≈0.4 - 0.6 MeV （corresponding to spin I≈80h）, which leads to clear upbending in moments of inertia （MoI＇s）. Our calculations have indicated that the hexadecapole deformation f14 influenced significantly the frequency of the rotational alignment of the proton 1/2＋[651] orbit.
From an inelastic excitation and breakup experiment with a12Be beam at 29 MeV/u,a large4He+8He cluster decay width of 1.1(2)MeV is determined for a state at an excitation energy of 10.3 MeV and with a spin parity of 0+.By using the R-matrix analysis,a cluster spectroscopic factor of 0.53(10)is extracted from the cluster partial width,providing a strong support for the clustering structure in12Be.A specially designed zero-degree telescope played an essential role in the present experiment and has been demonstrated to be a promising tool in future studies of the molecular-like resonances near the cluster separation threshold.
