Systematics of $\alpha$-decay transitions to excited states

We systematize the available experimental material concerning $\alpha$-decay transitions to low-lying excited states in even-even and odd-mass emitters. We generalize our previous theoretical prediction concerning the linear dependence between hindrance factors and the excitation energy for transitions in even-even $\alpha$ emitters. Thus, we show that $\alpha$ intensities for transitions to excited states depend linearly upon the excitation energy for all known even-even and odd-mass $\alpha$ emitters. It turns out that the well-known Viola-Seaborg law for $\alpha$-decay transitions between ground states can be generalized for transitions to excited states. This rule can be used to predict any $\alpha$-decay half-life to a low-lying excited state.

Figure 1

Spectroscopic factor versus the $\alpha$-formation probability for even-even, even-odd, odd-even, and odd-odd emitters.

Figure 2

Spectroscopic factor versus the fragmentation potential for even-odd, odd-even, and odd-odd emitters.

Figure 3

Intensity $I_J$ versus the excitation energy in the daughter nucleus $E_J$, $1\le J\le 6$, in even-even nuclei and for odd-mass favored and unfavored transitions.

Figure 4

Logarithm of the partial half-life versus the generalized Viola-Seaborg parameter (13) for even-even, odd-mass favored, and odd-mass unfavored emitters. Here we considered data with $1\le J\le 6$ in daughter nuclei.