Alpha Reduced Widths of Even-Mass Polonium Nuclei

Abstract

An attempt is made to obtain the alpha decay rates of even-mass polonium nuclei as a product of two factors: (a) the probability of occurrence of an alpha cluster in a surface well, and (b) the decay rate when an alpha cluster is already formed there. From a comparison with the empirical values, it seems that our method for calculating the decay rates is valid. It is shown that the break in alpha reduced width on going from ${\mathrm{Po}}^{210}$ to ${\mathrm{Po}}^{212}$ can be interpreted as due to a break in the well width. It is suggested that the nuclear surface of ${\mathrm{Pb}}^{206}$ is considerably more diffuse than that of doubly magic ${\mathrm{Pb}}^{208}$. It is also pointed out that our method gives a larger probability of finding an alpha cluster for ${\mathrm{Po}}^{210}$ than for ${\mathrm{Po}}^{212}$, whereas the Mang theory leads to the opposite result---a larger probability for ${\mathrm{Po}}^{212}$.