Half-lives and fine structure for the α decay of deformed even-even nuclei

The alpha-decay properties of well-deformed even-even nuclei are systematically calculated within the multichannel cluster model (MCCM). Instead of working in the WKB framework, the quasibound solution to the coupled Schrodinger equation is presented with outgoing wave boundary conditions, and the coupling potential is taken into full account in terms of the general quantum theories. The calculated alpha-decay half-lives are found to agree well with the experimental data with a mean factor of less than 2. The fine structure observed in alpha decay is also well reproduced by the four-channel microscopic calculation. Very strikingly, the MCCM can give relatively precise descriptions of the branching ratio to excited 4(+) states, which is often overestimated in the usual WKB calculations. We expect it to be a significant development of theoretical models toward quantitative descriptions of alpha transitions to high-spin daughter states.