Ionel Stetcu

When two atomic nuclei collide, the outcome depends on their energy and the angle at which the fragments fly apart. Typically, such calculations demand enormous computing power, and accuracy hits a wall due to approximations.

A uranium-235 nucleus that captures a slow neutron doesn't immediately fly apart into fragments. Instead, it seems to get stuck in two 'pits'—states with different shapes. The first, the ground state, is a slightly elongated drop. The second, the isomeric state, is a drop stretched further but not yet torn.