This award supports the participation of Prof. John O. Rasmussen of the University of California, Berkeley in a program of cooperative research with Prof. Raul Donangelo and others at the Federal University of Rio de Janeiro, and Prof. Mahir Hussein of the University of Sao Paulo. In this project, two-dimensional calculations of tunneling processes in heavy ion transfer, fission, and fusion will be performed. These calculations, which represent a significant extension of earlier one-dimensional work, should lead to an increased understanding of the role played by tunneling processes in heavy-ion nuclear reactions. Earlier collaborative research projects of these groups, supported by the National Science Foundation, resulted in an understanding of heavy-ion scattering and neutron transfer processes that was reported in several publications. However, as the simpler questions about these processes have been answered, and as improved computational facilities are now available, it has become both necessary and possible to extend the initial one-dimensional analyses to two dimensions, and particularly to study the role of tunneling in these reactions. Second-order multidimensional effects, such as those arising from the molecular cranking inertia, should also be included. The Brazilian collaborators have already developed and tested multidimensional computer codes which incorporate some, but not all, of the effects required; the U.S. investigators are developing additional codes themselves and, in addition, have access to some codes developed at the Lawrence Berkeley Laboratory. In addition, more substantial computer facilities are available at Berkeley than in Brazil. Therefore, the joint extension of the Brazilian codes, the incorporation of the LBL codes, and the performance of the computations at Berkeley represents an efficient collaboration which should result in a greater understanding of nuclear processes in general.
