Q-alpha values in superheavy nuclei from the deformed Woods-Saxon model

Abstract

Masses of superheavy (SH) nuclei with $Z=98-128$, including odd and odd-odd nuclei, are systematically calculated within the microscopic-macroscopic model based on the deformed Woods-Saxon potential. Ground states are found by minimizing energy over deformations and configurations. Pairing in odd particle-number systems is treated either by blocking or by adding the BCS energy of the odd quasiparticle. Three new parameters are introduced which may be interpreted as the constant mean pairing energies for even-odd, odd-even and odd-odd nuclei. They are adjusted by a fit to masses of heavy nuclei. Other parameters of the model, fixed previously by fitting masses of even-even heavy nuclei, are kept unchanged. With this adjustment, the masses of SH nuclei are predicted and then used to calculate $α$-decay energies to be compared to known measured values. It turns out that the agreement between calculated $Q_α$ values with data in SH nuclei is better than in the region of the mass fit. The model overestimates $Q_α$ for $Z=111-113$. Ground state (g.s.) configurations in some SH nuclei hint to a possible $α$-decay hindrance. The calculated configuration-preserving transition energies show that in some cases this might explain discrepancies, but more data is needed to explain the situation.