Comment on “Compound nucleus aspect of sub-barrier fusion: A new energy scaling behavior”

We comment on a recently published paper by R. Wolski entitled “Compound nucleus aspect of sub-barrier fusion: A new energy scaling behavior” [1], which claims that the sub-barrier fusion is determined mostly by the $Q$ value of the compound nucleus formation. This ignores the dynamical channel-coupling effects at near-barrier energies. We demonstrate that this simplified scaling of fusion cross sections is not a common case and has no predictive power.

Figure 1

Scaled fusion cross sections for the indicated reactions. The systematics of Ref. [1] is shown schematically by the dashed curve. The experimental data are from: ${}^{16}\mathrm{O}$+${}^{144,154}\mathrm{Sm}$ [11], ${}^{40}\mathrm{Ca}$+${}^{96}\mathrm{Zr}$ [12], ${}^{40}\mathrm{Ca}$+${}^{40}\mathrm{Ca}$ [13], ${}^{48}\mathrm{Ca}{+}^{48}\mathrm{Ca}$ [14], ${}^{17}\mathrm{F}$+${}^{208}\mathrm{Pb}$ [15], ${}^{19}\mathrm{F}$+${}^{208}\mathrm{Pb}$ [16], ${}^{16}\mathrm{O}$+${}^{208}\mathrm{Pb}$ [17], ${}^{40}\mathrm{Ar}$+${}^{112}\mathrm{Sn}$ [18], ${}^{64}\mathrm{Ni}$+${}^{64}\mathrm{Ni}$ [19], ${}^{30}\mathrm{Si}$+${}^{58}\mathrm{Ni}$ [20], and ${}^{12}\mathrm{C}$+${}^{14}\mathrm{N}$ [21].

Figure 2

Reduced fusion cross sections for the ${}^{64}\mathrm{Ni}+{}^{64}\mathrm{Ni}$ and ${}^{58}\mathrm{Ni}+{}^{64}\mathrm{Ni}$ systems [19]. $V_B$ is the Bass barrier [22]. The geometrical cross section is calculated as ${\sigma }_{\mathrm{geom}}=\pi {\left[1.16\left(A_p^{1/3}+A_t^{1/3}\right)\right]}^2$.

Figure 3

Fusion cross sections for the ${}^{17}\mathrm{F}+{}^{208}\mathrm{Pb}$ [15] and ${}^{19}\mathrm{F}+{}^{208}\mathrm{Pb}$ [16] systems.