Multiple scattering approach to continuum state with generally shaped potential

We present a new scheme for solving the scattering problem for an arbitrarily shaped potential cell that avoids the well known convergence problems in the angular momentum expansion of the cell shape function. Tests of the method against analytically soluble separable model potentials, with and without shape truncation, have been performed with success. By a judicious choice of the shape of the cells partitioning the whole molecular space and use of empty cells when necessary, we set up a multiple scattering scheme that leads to a straightforward generalization of the same equations in the muffin-tin approximation. For example l_max in the angular momentum expansion can still be chosen according to the rule l_max ∼ kR, where R is the radius of the bounding sphere of the cell and all the matrices appearing in the theory are square matrices.