Partial Summation Method for XANES Calculation

Abstract
A new efficient multiple-scattering method is proposed, which is based on partitioning method developed by one of the authors. This method includes important multiple-scatterings in infinite order, which is similar to the finite path-by-path approach. We also obtain some symmetric relations and recurrence formulas of the free electron propagators G_LL' to reduce computation time. Some illustrative examples are shown. For small systems convergence is easily attained, however the efficiency is not so remarkable. For large systems the convergence is rather slow, however it is accelerated by including the photoelectron wave damping. The computation time is about 5% of that for the full multiple scattering calculation for a cluster with 27 Fe atoms. The convergence is dependent on the system, whether it is closely packed or not.