Fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems

Existing data on near-barrier fusion excitation functions of medium and heavy nucleus-nucleus systems have been analyzed by using a simple diffused-barrier formula derived assuming the Gaussian shape of the barrier-height distributions. The fusion cross section is obtained by folding the Gaussian barrier distribution with the classical expression for the fusion cross section for a fixed barrier. The energy dependence of the fusion cross section, thus obtained, provides good description to the existing data on near-barrier fusion and capture excitation functions for medium and heavy nucleus-nucleus systems. The theoretical values for the parameters of the barrier distribution are estimated which can be used for fusion or capture cross-section predictions that are especially important for planning experiments for synthesizing new superheavy elements.

Figure 1

Comparison of the measured capture excitation functions (full circles) for ${}^{16}\mathrm{O}+{}^{144}\mathrm{Sm}$ with predictions (solid lines) of the diffused-barrier formula.

Figure 2

Comparison of the measured capture excitation functions (full circles) for ${}^{40}\mathrm{Ca}+{}^{124}\mathrm{Sn}$ with predictions (solid lines) of the diffused-barrier formula.

Figure 3

Comparison of the measured capture excitation functions (full circles) for ${}^{36}\mathrm{S}+{}^{90,96}\mathrm{Zr}$ for with predictions (solid lines) of the diffused-barrier formula.

Figure 4

Calculated capture excitation functions for ${}^{48}\mathrm{Ca}+{}^{244}\mathrm{Pu}$, ${}^{243}\mathrm{Am}$, ${}^{245}\mathrm{Cm}$, ${}^{248}\mathrm{Cm}$, ${}^{249}\mathrm{Bk}$, and ${}^{249}\mathrm{Cf}$.