An improved Gamow-like formula for α-decay half-lives

Abstract

An improved Gamow-like (IMGL) formula for α-decay half-lives is proposed by introducing an accurate charge radius formula, an analytic expression of assault frequency, the angular momentum taken by α-particle and the isospin effect. The parameters of the IMGL formula are obtained by fitting the experimental α-emitter data with Zp=52–118 (515 α emitters. Zp is the charge number of a parent nucleus) and those with Zp=92–118 (178 α emitters). Correspondingly, the IMGL formula with the parameters fitted the experimental data with Zp=52–118 is named as the IMGL1 formula and the other one is called as the IMGL2 formula. By using the two formulas, a large number of α-decay half-lives are calculated. It is shown that the accuracy of the IMGL1 and IMGL2 formulas is improved significantly compared to their predecessors. Moreover, the accuracy of the IMGL1 and IMGL2 formulas is higher than that of other types of empirical formulas, including the Royer formula, modified Royer (MR) formula, Viola-Seaborg-Sobiczewski (VSS) formula, modified Viola-Seaborg-Sobiczewski (MVSS) formula, formula proposed by Y. Qian and Z. Ren (YQZR) and modified YQZR (MYQZR) formula. In addition, the experimental α-decay half-lives of the synthesized newly neutron-deficient Actinide nuclei and the superheavy nuclei are reproduced well by the two formulas. Then, the α-decay half-lives of the neutron-deficient nuclei with Zp=94-119 are predicted within the IMGL2 formula because its accuracy is higher slightly than that of the IMGL1 formula. Finally, the competition between α-decay and spontaneous fission (SF) with Zp=120 α-decay chains is investigated in detail within the IMGL2 formula and the modified Swiatecki's formula. The predictions of the neutron-deficient nuclei with Zp=94-119 and the superheavy nuclei with Zp=120 are useful for identifying the new nuclides in future experiments.