engleski

Structure of neutron-rich Beryllium isotopes

States of 10Be have been investigated in single-neutron transfer reactions on 9Be as well as in two-proton pick-up reactions on 12C. Excited states of 11Be have been studied with several transfer reactions. Nine states between 3.96 MeV and 25.0 MeV excitation energy show the characteristic energy dependence of a rotational band. The deduced large moment-of-inertia of this band is consistent with a two-alpha structure with large deformation. For 12Be four high lying states at 7.30 MeV, 10.7 MeV, 14.6 MeV and 21.7 MeV, which were observed in the 9Be(15N, 12N)12Be reaction, also form a rotational band with almost the same moment-of-inertia as for 11Be, using the tentative spin assignments of 2+ - 8+. The molecular rotational bands of 11Be and 12Be are well populated, when 9Be is used as the core and neutrons are added in the transfer reaction. If 10Be is used for the core, states of molecular structure are not populated.

cluster states; transfer reactions; 10Be; 11Be; 12Be

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