A NEW COMPUTATIONAL ALGORITHM FOR GREENS-FUNCTIONS - FOURIER-TRANSFORM OF THE NEWTON POLYNOMIAL EXPANSION

A new iterative method to compute the Green's function for continuum s ystems is presented. It is based on a Newton polynomial expansion of t he corresponding propagator, followed by accurate half-Fourier transfo rmation. The new technique is remarkably stable, accurate and can hand le very large systems. We apply the new method to the calculation of t hree-dimensional quantum reaction probabilities for the initial state- selected D + H-2(n,j) --> DH + H reaction. We find excellent agreement with previous results, requiring very modest amounts of CPU time.