# RPATH

### From FEFF

* Useful *

RPATH rpath

The RPATH card determines the maximum effective (half-path) distance, rpath, of a given path. RPATH is equivalent to the RMAX card in the FEFF7 code. We changed the name because it provides a clearer distinction between the max distance in the MS path expansion and that for FMS calculations. Typically rpath is needed for EXAFS calculations only to set limits on the number of calculated paths. Note that rpath is one-half of the total path length in multiple-scattering paths. Setting this too large can cause the heap in the pathfinder to fill up. Default is rpath = 2.2 times the nearest neighbor distance. Since the multiple scattering expansion is unstable close to the absorption edge, the path (MS) expansion should be used only for EXAFS calculations or for diagnosing the XANES or LDOS calculations. If you use FMS for XANES calculations, better results are obtained without the MS contribution. For EXAFS analysis this card is extremely useful, since it cuts off long paths which contribute only at high R values in R-space.

* include MS paths with effective length up to 5.10 Ang RPATH 5.10