9408795 Sorensen The research proposed here has two main objectives. The first is to develop and test new algorithms and approaches for addressing computational operations that are encountered in a wide range of computational science and engineering applications (e.g.,eigenproblems,linear equation solvers an propagation methods). The second is to enhance significantly the range of chemical reactions that can be studied with ab initio quantum scattering methods (e.g., four-atom systems and heavier three-atom systems). The basic approach is to bring together in a single research team knowledge of an experience with the most advanced numerical algorithms for solving the kinds of mathematical problems that are at the core of these scattering methods.