Imprint of adiabatic structures in monopole excitations ofBe12

Abstract

The monopole excitations (0 + g.s. → 0 + ex ) of light neutron-excess systems 12 Be = α + α + 4N are investigated by the generalized two-center cluster model. We analyze the mechanism of an enhancement of the monopole strength in connection to structures of adiabatic energy surfaces as a function of an α-α distance. The crossing of two adiabatic energy surfaces, which have different intrinsic configurations, increases the monopole strength. Furthermore, we find that the monopole strength is strongly enhanced by a smooth connection in the adiabatic energy surface from the ground 0 + state to the excited 0 + state. A comparison of the calculated strength with the respective single particle limit is also discussed.

Toroidal, compressive, and E1 properties of low-energy dipole modes in Be10

“…[43]). The ISM strengths in Be isotopes have been theoretically studied by cluster models and suggested to be a good probe for cluster states [43][44][45]. One of the authors, Y. K-E., has studied the E1 and compressive ISD strengths of Be isotopes and discussed the dipole excitations for cluster states [46].…”

Isoscalar dipole transition as a probe for asymmetric clustering

“…This finding boosted the studies of the cluster states by using the monopole transition as a probe. In these days, various cluster states in stable and unstable nuclei [33][34][35][36][37][38][39][40] are discussed on the basis of their enhanced monopole strengths.…”

Studies of Light Neutron-Excess Systems from Bounds to Continuum

“…We have found that, in 10,14 Be, the ionic structures, which are embedded in continuum, are realized as the cluster's excitation modes from the bound states. In 16 Be, an energy level, which can be considered as the α+α analog state, is obtained in 16 Be.…”

“…Furthermore, two resonant states, which have the ionic structures, are identifie by solving the 6 He+ 8 He collision. These resonant states correspond to the cluster's excitation modes from the bound states: The 0 + 3 state, which has the ionic structure of 6 In 10 Be, one of two 0 + states above the α threshold becomes a broad continuum state, but, in 14 Be, both unbound 0 + states becomes the resonant states. This is because of the increase of excess neutrons.…”

“…In 12 Be for instance, this model can handle the formation of an atomic structure of 6 He+ 6 He, a e-mail: itomk@kansai-u.ac.jp ionic structures of α+ 8 He and 5 He+ 7 He, and covalent MO structures in a consistent manner. In this report, we mainly investigate the intrinsic structure of 12 Be and reaction process induced by α+ 8 He slow collision, and such investigations are extended to even Be isotope of 8,10,12,14,16 Be.…”