Characteristics of Coulomb fission

Within an extended semiquantal theory we perform large-sized coupled-channel calculations involving 260 collective levels for Coulomb fission of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$. Differential Coulomb fission cross sections are studied as a function of bombarding energy and impact parameter for several projectiles. In the Xe + U case, total cross sections are also given. We find a strong dependence on projectile charge number, $P^{\mathrm{CF}}\left(180\mathrm{}°\right)\sim {\left(Z_p\right)}^6$ in the region $50\le Z_p\le 92$ for a fixed ratio $\frac{E}{E_{\mathrm{Coul}}}$, which might be helpful to separate Coulomb fission experimentally from sequential fission following transfer reactions. Since the cross sections are sensitive to the moment of inertia $\ominus$ at the saddle point, Coulomb fission can serve as a tool to investigate the dependence of $\ominus$ on elongation. The fragment angular distribution exhibits deviations from $\frac{1}{{sin\theta }_f}$ which are pronounced at low incident energies. Our theory indicates that the recently measured Xe + U fission cross sections contain a major fraction of Coulomb-induced fission at $E\le 0.85E_{\mathrm{Coul}}$.