Competition between α decay and proton radioactivity of neutron-deficient nuclei

Abstract

The $\ensuremath{\alpha}$ decay and proton radioactivity half-lives of some neutron-deficient nuclei are calculated using an effective liquid drop model (ELDM). It is found that the experimental half-lives of the two decay modes and the dominant decay mode can be well reproduced by the ELDM. Moreover, the predicted penetration probabilities ($P$) of proton radioactivity by the ELDM are in agreement with those by a microscopic model (MM). This allows us to make predictions on the competition of the two decay modes for nuclei whose experimental data are not available, which are useful for future measurements. In addition, the comparison between the predicted reduced proton radioactivity half-lives by the ELDM and the ones by a standard formula suggests that one is unlikely to observe large angular momentum transfers for nuclei with a very large Coulomb parameter $\ensuremath{\chi}$. Last, we find that in most isotope chains the proton radioactivity is the dominant decay mode for nuclei that are very close to the proton drip line. But with increasing neutron number $N$ the main decay mode is changed into $\ensuremath{\alpha}$ decay. With the decay energies the decay mode anomaly of $^{184}\mathrm{Bi}$ is discussed.