The excitation energy dependence of the competition between neutron emission and fission has been calculated for nuclei in the vicinity of the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ closed shell. A two-center model has been used to calculate single-particle effects on the nuclear level density as well as on the barrier heights. Comparison with experiment demonstrates the importance of including the dependence of the single-particle level density on deformation.

• Received 21 April 1972

DOI:https://doi.org/10.1103/PhysRevLett.28.1726