Hello, I collected As K EXAFS data and created a cluster which could represent the "probable geometry". I have an ATOMS file with coordinates of the atoms in a triclinic unit cell. ATOMS did its thing but FEFF refused to process the data and generated an error: Feff 6L.02 No atoms or overlap cards for unique pot 1 Cannot calculate potentials, etc. Fatal Error: at RDINP Then I filled the empty space around the cluster with hydrogen atoms on a grid, hoping that FEFF would like it more, but the same error came. Short of creating a complete structure (of some sort) with the cluster embedded in it, what can I do to make this work? Thank you, Juro Majzlan ---------------------------------- Juraj Majzlan Institute of Mineralogy and Petrology Albert-Ludwig-University of Freiburg Albertstrasse 23b Freiburg, D-79104, Germany telephone +49-761-203-6416 fax +49-761-203-6407 http://www.minpet.uni-freiburg.de