Developed formula for calculating the alpha decay half-lives of americium isotopes

Abstract

Americium (Am), an artificial element and therefore for which no standard atomic weight can be determined, most of its isotopes decay by emitting alpha particles. Like all artificial elements, Am has no known stable isotopes. As early as 1911, Geiger and Nuttall gave a linear relationship between the logarithm of the half-life and the energy of alpha decay, which was then called the Geiger–Nuttall law. In 1966, Viola–Seborg generalized the Geiger–Nuttall law and proposed the Viola–Seborg formula. The half-lives calculated for the preferred a decay of even–even nuclei by this formula agree well with experimental data. Royer's formula, one of the most popular generalizations, is widely used in calculating and predicting alpha decay half-lives.

We calculated the alpha decay half-lives of americium isotopes (Z = 95) with mass numbers ranging from 223 to 243, using a developed formula similar to Royer's formula. Our investigation used the Coulomb potential and the centrifugal potential resulting from the nuclear layer model to obtain the developed formula for calculating the half-lives of the unfavorable alpha decay of americium isotopes. Our calculations took into account the experimental values ​​of Q_a(MeV). We analyzed the behavior of the angular momentum lm and its effect on the half-lives of unfavored alpha decays and also examined the effect of the presence of neutrons in subshells immediately following a subshell ending with a magic number. Based on this, we were able to calculate the half-lives of the unfavorable alpha decay of americium ( ) with a better standard deviation than that obtained by the Royer's formula and (Royer-am) improved formula.