Editing EXAFS (section)

==Pre-processing==

For each structure you want to analyze: 

* Create a folder. 
* Put the VASP output in that folder. 
* Convert the structure to a .cif file. 
* Convert the .cif to feff.inp using this page: http://millenia.cars.aps.anl.gov/webatoms/. If that page is offline, open Artemis (part of Demeter package, you need to do this in Windows), file, open project or data, pick your cif file. 
* In the webatoms page or in Artemis, select the edge, select feff6_element style, and select the atom that will be the center of the analysis. In Artemis, clic in "Run Atoms". It will generate a file that contains something like this: 
 (...)
 POTENTIALS
 *   ipot   Z  element        l_scmt  l_fms   stoichiometry
     0     26     Fe           2       2       0.001
     1     6      C            1       1       64
     2     7      N            1       1       4
 
 
 ATOMS                  * this list contains 71 atoms
 *   x          y          z     ipot tag           distance
    0.00000    0.00000    0.00000  0  Fe70          0.00000
   -1.82232   -0.51126   -0.02496  2  N69.1         1.89285
   -0.46930    1.83344   -0.04068  2  N67.1         1.89298
    1.82348    0.51118   -0.03720  2  N66.1         1.89414
    0.46853   -1.83477   -0.04752  2  N68.1         1.89424
   -2.56146    0.65484   -0.06360  1  C17.1         2.64460
    1.84706   -1.89028   -0.09876  1  C33.1         2.64472
    2.56107   -0.65476   -0.08652  1  C34.1         2.64486
   -1.84924    1.89065   -0.07752  1  C18.1         2.64580
 (...) 
* Save that file as '''feff.inp''' and place it in the folder where you are runnig your analysis. 
* Be sure that '''all''' elements listed in POTENTIALS (ipot) appear in ATOMS (ipot). 
* If there is an element missing in ATOMS, remove the respective entry (full line) in POTENTIALS. 
* The list of ipot in POTENTIALS '''must''' be continuous and start from 0. If you have a discontinuity (i.e. 0, 1, 3, 4), you must change the ipot numbers both in POTENTIALS and ATOMS (i.e. 3=>2 and 4=>3).