Peter Zavalij wrote: > > Bob, > Thank you for the clarification. I never had doubts that GSAS handles fixed origin > issue properly but also never understand how it > is done. This way has one big advantage over user fixed origin -- it yields standard > uncertainties for all atoms and therefore for > all distances, etc. > Peter Zavalij >
When there is a 1bar site it is automatically chosen as the origin of the unit cell. Any other choice would require adding a extra shift parameter to the X, Y and Z notation in generation the matrices which perform the symmetry operations. Allen
