Angular momentum generation before and after scission

During its evolution towards scission, the fission complex acquires several tens of MeV of internal excitation in the form of quasi particles which each carries some angular momentum. As scission is approached, the geometric restrictions favor population of orbitals having angular momentum perpendicular to the fission axis. The observed saw-tooth patterns of the mass dependence of the neutron multiplicity and the angular momentum emerge if the perpendicular angular momenta have thermal distributions, provided that proper account is taken of shell and pairing effects in the level densities of the distorted fragments at scission. After scission, the torque exerted by the Coulomb force on the deformed fragments may amplify their angular momenta by 1-2 units.