Coupled-channels study of fine structure in theαdecay of well deformed nuclei

Abstract

We formulate a theoretical model for the α decay of well-deformed even-even nuclei based on the coupledchannel Schrödinger equation. The α-decay half-lives and fine structures observed in α decay are well described by the five-channel microscopic calculations. Since the branching ratios to high-spin states are hard to understand in the traditional α-decay theories, this success could be important to interpret future observations of heavier nuclei. It is also found that the α transition to high-spin states is a powerful tool to probe the energy spectrum and deformation of daughter nuclei.

Coupled-channels study of fine structure in theαdecay of platinum isotopes

“…Recently, within the coupled-channels framework, we have employed two different techniques to deal with the coupling interaction matrix between channels. We have performed separate four-channel and five-channel calculations for well-deformed rotational α emitters [7,8]. The theoretical results reproduced well the available experimental data concerning α-decay halflives and fine structures.…”

“…[8], the parameter set shown in Ref. [8] gives smaller values of r 0 and a, leading to an underestimation of the tunneling rate.…”

“…In our calculations, the nuclear potential between the α cluster and the deformed core nucleus is approximated by a deformed Woods-Saxon field [8]. Its shape is defined by the radius, R 0 = r 0 A 1/3 d , and diffuseness, a, which are 037301-2 parametrized in terms of the isospin-dependent form.…”

“…Our approach is essentially based on the stationary coupled-channel Schrödinger equation with outgoing wave boundary conditions. The radial wave functions u J n I (r) are obtained by integrating numerically the following coupled equations [4,5,7,8]:…”

“…Some semiclassical methods, based on the onedimensional Wentzel-Kramers-Brillouin (WKB) semiclassical approximation, have been extended from the spherical picture to a deformed case in a phenomenological manner, such as the simple WKB barrier penetration approach [1], the generalized liquid drop model (GLDM) [2], and the unified model for α decay and α capture (UMADAC) [3]. The other group uses the stationary coupled-channels approach [4][5][6][7][8], where the three-dimensional Schrödinger equation is exactly solved with outgoing wave boundary conditions. The second approach is less documented than the semiclassical calculation.…”