Hi Bruce, first of all a welcome back from the UK. Good to see your messages popping up in the mailing list again. Hope you are relaxed enough to get back to business... I am glad to hear that implementing a "bound" function in ARTEMIS is not difficult to handle. I agree with your point that the function need not be implemented in the IFEFFIT library itself. It is after all just an interface which produces the functions that Matt described earlier. Another subject: Did you consider implementing the "load GDS sheet" and "save GDS sheet" options we discussed earlier? This would be great for text editor freaks (like me, I confess...), as you can write your variable definitions external and crank them back into ARTEMIS to do the fitting business for you. Norbert -- Dr. rer. nat. Norbert Weiher (norbert.weiher@manchester.ac.uk) School of Chemical Engineering and Analytical Science Sackville Street, Manchester, M60 1QD - Phone: +44 161 306 4468