Dear users, I was able to install iffefit on linux. From the command line I run: feff6 feff.inp This worked fine and several feffnnnn.dat files were generated. Then, I wrote an input script, tmp.iff (shortened list of paths here), for ifeffit as follows: # tmp.iff path(1, file=feff0001.dat, s02 = 0.9, sigma2 = 0 .001) path(2, file=feff0002.dat, s02 = 0.9, sigma2 = 0 .001) path(3, file=feff0003.dat, s02 = 0.9, sigma2 = 0 .001) path(4, file=feff0004.dat, s02 = 0.9, sigma2 = 0 .001) path(5, file=feff0005.dat, s02 = 0.9, sigma2 = 0 .001) path(6, file=feff0006.dat, s02 = 0.9, sigma2 = 0 .001) path(7, file=feff0007.dat, s02 = 0.9, sigma2 = 0 .001) path(8, file=feff0008.dat, s02 = 0.9, sigma2 = 0 .001) path(9, file=feff0009.dat, s02 = 0.9, sigma2 = 0 .001) path(10, file=feff0010.dat, s02 = 0.9, sigma2 = 0 .001) path(11, file=feff0011.dat, s02 = 0.9, sigma2 = 0 .001) ff2chi(1-11, group=mycalc) fftf(mycalc.chi, kmin=1, kmax=15, dk=0.5, kweight=2.0, kwindow='hanning') # My aim here is to sum the paths to generate chi(k). Now if I run the following command: ifeffit -x tmp.iff the following output is printed on the screen: reading feff0101.dat reading feff0102.dat reading feff0103.dat reading feff0104.dat reading feff0105.dat reading feff0106.dat reading feff0107.dat reading feff0108.dat reading feff0109.dat reading feff0001.dat reading feff0002.dat reading feff0003.dat reading feff0004.dat reading feff0005.dat reading feff0006.dat reading feff0007.dat reading feff0008.dat reading feff0009.dat reading feff0010.dat reading feff0011.dat It appears that the feffnnnn.dat files were read successfully. However, no mycalc.chi output was produced by ff2chi() [and therefore no mycalc.chir_* output was produced by fftf()]. I don't know if my approach is missing an important step or my entire procedure is nonsensical. Thanks a lot!