invited papers
Some of the advanced EXAFS analysis features of FEFF and FEFFIT are described. The scattering path formalism from FEFF and cumulant expansion are used as the basic building blocks of EXAFS analysis, giving a flexible and robust parameterization of most EXAFS problems. The ability to model EXAFS data in terms of generalized physical variables is shown, including the simultaneous refinement of two different polarizations for Co EXAFS data of .