An Estimation of the Optical Constants of Copper Based on the FEFF 9 Package

Abstract

The FEFF software package is based on a first-principles real space Green function (RSMS) scattering theory to calculate X-ray absorption fine-structure (XAFS), and forward scattering amplitudes (FSA). From these, an energy-dependent complex dielectric constant can be calculated, and from it other “optical constants”, like the complex index of refraction, absorption coefficient, the reflectance, and energy-loss function, can be derived. A procedure to estimate these using FEFF version 9 is outlined applied to crystalline metallic copper as an example, and the results compared to values taken from the literature.