FEFF 6 has been extensively tested but occasionally new bugs show up. In an effort to maintain trouble-free codes we take all bug reports seriously. Often we receive reports by users of older versions of FEFF of bugs that are fixed in the latest releases. Other code failures can often be traced to input file errors, sometimes quite subtle. An example would be non-physical widely spaced distributions of atoms. Symptoms of this common problem are very large muffin-tin radii (see the header of any .dat file) and possibly a failure of the phase-shift program to converge. Another example is an error in assigining potential indices; the first atom with a given potential index must have the geometry representative of this potential type. This is sometimes fixed by using a somewhat larger cluster; in fact it is usually desirable to have a larger cluster for potential construction than that used in the XAFS calculation due to errors in the potentials at surfaces. Unless the atom distribution is physically possible, you can expect the code to have problems. If, after you have verified that your input file is not the problem, the problem persists, please contact us at the e-mail addresses listed in Sec. 1. To address your problem, we need the following information:
chi.dat) or log file.