Dear Scott, The answer to this question depends on the compounds you're interested with and probably also on the software you have access to. In principle all computational chemistry software can export a molfile of the optimised structure. Using xyz coordinates in the molfile you can easily rig a feff input file. Best advice is probably to get in touch with a molecular modelling group and ask them to do the structure optimisations. If that's not an option, you could try Gaussian. Fairly expensive, but in combination with Gaussview it's reasonably easy to get the structure optimisation going. Gamess should do the trick for free. ADF is also an option and VASP can even handle periodic systems decently. But as i said initially, the best advice is to collaborate with a good molecular modelling group. Regards, Eric -- Eric Breynaert Centrum voor Oppervlaktechemie en Katalyse Departement Microbiële en moleculaire systemen (M²S) - KU Leuven Kasteelpark Arenberg 23 - bus 2461 B-3001 Leuven Tel: +3216321598 Fax: +3216321998