Fusion behavior in time-dependent Hartree-Fock calculations ofKr86+La139andKr84+Bi209collisions

Results are presented for time-dependent Hartree-Fock calculations of head-on collisions of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$ + ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ and ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ + ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$. The two-body effective interaction employed is the finite-range Skyrme II potential. For both systems fusion is observed in a broad energy region at moderately high energies above the Coulomb barrier and fusion-like events are also found for a smaller range of energies near the barrier. The ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$ + ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ system exhibits resonance-like behavior in both energy regimes. From non-head-on collisions ($L\ne 0$), an estimate is made of a lower limit for the fusion cross section of ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ + ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ → ${}_{}{}^{293}{}_{}{}^{}119$* at $E_{\mathrm{lab}}=875\mathrm{}$ MeV. For both systems a fusion window exists beyond the maximum energy for which fusion is seen for $L=0\mathrm{}$. The fusion behavior is found to be sensitive to the two-body effective interaction used. It is shown that, in numerical Peaceman-Rachford calculations, the occurrence of fusion and the amount of energy dissipation can depend upon the magnitude of the time step used.