The potential energy governing α emission has been determined within a liquid drop model including proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives have been deduced from the WKB barrier penetration probability as for a spontaneous asymmetric fission. The RMS deviation between the theoretical and experimental values of log 10[T1/2(s)] is only 0.63 for a recent data set of 373 α emitters and 0.35 for the subset of even-even nuclides. Predictions for the heaviest and superheavy elements are presented as well as simple analytical formulae for log 10[T1/2(s)].

The α particle preformation in the even-even nuclei from 108 Te to 294 118 and the penetration probability have been studied. The isotopes from Pb to U have been firstly investigated since the experimental data allow us to extract the microscopic features for each element. The assault frequency has been estimated using classical methods and the penetration probability from tunneling through the Generalized Liquid Drop Model (GLDM) potential barrier. The preformation factor has been extracted from experimental α decay energies and half-lives. The shell closure effects play the key role in the α preformation. The more the nucleon number is close to the magic numbers, the more the formation of α cluster is difficult inside the mother nucleus. The penetration probabilities reflect that 126 is a neutron magic number. The penetration probability range is very large compared to that of the preformation factor. The penetration probability determines mainly the α decay half-life while the preformation factor allows us to obtain information on the nuclear structure. The study has been extended to the newly observed heaviest nuclei.

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