Fission energy surfaces and ternary fission

A three-center phenomenological model, able to explain qualitatively the re cently obtained experimental results concerning the quasimolecular stage of a Light-particle accompanied fission process is presented. It was derived from the Liquid drop model under the assumption that the aligned configurat ion, with the emitted particle between the light and heavy fragment, is rea ched by increasing continuously the separation distance, while the radii of the heavy fragment and of the light particle are kept constant. In such a way, a new minimum appears in the deformation energy at a separation distan ce very close to the touching point. This minimum allows the existence of a short-lived quasi-molecular state, decaying into the three final fragments . The influence of the shell effects is discussed. The half-lives of some q uasimolecular states which could be formed in the Be-10 and C-12 accompanie d fission of Cf-252 are roughly estimated to be of the order of 1 ns and 1 ms, respectively.