A systematic study on $\alpha$-decay fine structure is presented for even-even nuclei in the range $78\le Z\le 102$. The penetration probability is obtained from the WKB approximation in combination with the Bohr-Sommerfeld quantization condition. The potential barrier is numerically constructed in the well-established double-folding model for both Coulomb and nuclear potentials. A realistic M3Y interaction, based on the $G$-matrix elements of the Paris $NN$ potential, has been used in the folding calculation. The local approximation for the nondiagonal one-body density matrix in the calculation of the exchange potential was included by using the harmonic oscillator representation of the nondiagonal density matrix of the $\alpha$ particle. The computed partial half-lives and branching ratios are compared with the recent experimental data and they are in good agreement.

• Received 24 May 2015
• Revised 29 June 2015

DOI:https://doi.org/10.1103/PhysRevC.92.014619