SYMMETRICAL MULTI-FRAGMENTATION BARRIERS AND THEIR TEMPERATURE-DEPENDENCE IN MEDIUM AND HEAVY MASS NUCLEI

Shapes consisting of a series of pear-like bodies surrounding an inner joined sphere are assumed to be those associated with symmetric fissi on or fragmentation into two or more fragments. The shapes evolve smoo thly from that of an initial spherical nucleus to the scission point. The shapes are calculated using a generalization of the cassinian oval oid shape parameterization, which has been demonstrated to be a good a pproximation for binary fission. Using this parameterization, fission barriers have been calculated for 2-, 3-, 4-, 6- and 8-fold multi-frag ment final states. Proximity effects are included. The temperature dep endence of these fission barriers is also calculated. The importance o f nuclear dynamics in determining the range in which static barriers a re sampled is discussed.