Nuclear and Coulomb breakup of the weakly bound ${}^6$Li nucleus with targets in the range from $A=59$ to 208

We have performed continuum discretized coupled channel (CDCC) calculations for the ${}^6$Li + ${}^{59}$Co, ${}^{144}$Sm, and ${}^{208}$Pb systems, to investigate the dependence of the relative importance of nuclear and Coulomb breakup on the target charge (mass) at near-barrier energies. The calculations were in good agreement with the experimental elastic scattering angular distributions for these systems and then their predictions to the nuclear, Coulomb, and total breakup were investigated. Although the relative importance of the nuclear breakup is, as expected, larger for lighter targets, this effect is not very pronounced. We also investigate a scaling of the nuclear breakup with the target mass and we compare the predictions for the integrated total breakup cross sections with experimental fusion cross sections at similar energies.

Figure 1

Elastic scattering angular distributions for the three systems investigated. The data for the ${}^{59}$Co (a), ${}^{144}$Sm (b), and ${}^{208}$Pb (c) targets are respectively from Refs. [22, 23] and [24].

Figure 2

Breakup angular distributions at three near-barrier energies for the systems discussed in the text. In each case, we show the total breakup cross section (solid lines) together with the cross sections for pure Coulomb (short-dashed lines) and pure nuclear (long-dashed lines) breakup. As in the previous figure, (a), (b), and (c) correspond, respectively, to results for the ${}^{59}$Co, ${}^{144}$Sm, and ${}^{208}$Pb targets.

Figure 3

The crossing angle, ${\theta }_0$, above which nuclear breakup dominates the breakup angular distribution. For details see the text.

Figure 4

Coulomb to nuclear ratio of integrated breakup cross section for the three systems under investigation.

Figure 5

Scaling of the nuclear breakup cross sections as a function of $A_{\mathrm{T}}^{1/3}$ for the systems discussed in the text, at $E_{\mathrm{c}.\mathrm{m}.}/V_{\mathrm{B}}=0.84$ (a), 1.00 (b), and 1.07 (c).

Figure 6

Scaling of the Coulomb breakup cross sections as a function of $Z_{\mathrm{T}}$ for the systems discussed in the text. (a), (b), and (c) correspond, respectively, to results at $E_{\mathrm{c}.\mathrm{m}.}/V_{\mathrm{B}}=0.84$, 1.00, and 1.07.

Figure 7

Comparisons of the fusion and the breakup cross sections for collisions of ${}^6$Li projectiles with the ${}^{59}$Co (a), ${}^{144}$Sm (b), and ${}^{208}$Pb (c) targets, at near-barrier energies.