The measured element distribution in collisions of ${}_{}{}^{86}{}_{}{}^{}\mathrm{Kr}$ with ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}$ at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=463\mathrm{}$ MeV is examined in the framework of the one-body dissipation model with an empirical potential energy surface deduced from fission. The fragment $Z$ distributions over the entire range of kinetic energy damping are consistent with a driftless nucleon diffusion process. No evidence is found for a fusion-fission component.

NUCLEAR REACTIONS ${}_{}{}^{166}{}_{}{}^{}\mathrm{Er}({}_{}{}^{86}{}_{}{}^{}\mathrm{Kr},A_L)A_H{E}_{\mathrm{c}.\mathrm{m}.\mathrm{}}=326\mathrm{} \mathrm{and} 463$ MeV. Measured $\sigma (A_L, Q \mathrm{value})$; deduced reaction mechanism.

• Received 23 September 1980

DOI:https://doi.org/10.1103/PhysRevC.23.2745