LANDAU-ZENER EFFECT IN CLUSTER DECAY

The influence of the Landau-Zener effect on the fine structure of the cluster decay phenomenon is evidenced. Estimations of hindrance factor s are reported for the C-14 emission from Ra-223. The half-lives are c alculated considering the cluster decay as a superasymmetric fission p rocess appealing to the Wentzel-Kramers-Brillouin penetrabilities. The excitation of the last unpaired nucleon is considered to be due mainl y to the Landau-Zener promotion mechanism. The deformation energy is c omputed in the framework Yukawa-plus-exponential model extended for bi nary systems with different charge densities and adding the specializa tion energy of the unpaired nucleon. The Werner-Wheeler approximation is used to compute the effective mass. Assuming molecular states durin g the disintegration, the superasymmetric two-center shell model is us ed to obtain the level scheme of the cluster decay. [S0556-2813(98)062 05-0].