Hello, it's me again, it was a pleasure for me to hear that IFEFFIT can now handle restraints. I read the documentation on handling them on the IFEFFIT homepage but one thing is still unclear: I see how you can say that a value should be near some number you know from other methods. But how do I apply a range? Of course, I could always use the midpoint of the restraint interval and use the way described - but can you do it in other ways? The last question concerns the weighting factor: Let's keep with Matt's example of setting a restraint on a distance to 2.54. If I use the weighting of 0.01 shown in the example, what would be the max. and min. values the fit can run to? Is it +/- 1 % deviation or something else? Cheers, Norbert -- Dr. rer. nat. Norbert Weiher (norbertweiher@yahoo.de) Laboratory for Technical Chemistry - ETH Hönggerberg HCI E 117 - 8093 Zürich - Phone: +41 1 63 3 48 32