Dear Franz, As far as I know it is not possible, even by using multiple wavelengths at a synchrotron. The problem is nothing to do with reflection overlap in the sense of overlapping peaks of different d spacings, but due to the direct overlap of reflections with the same d spacing. The problem is that you have collapsed 3D information into 1D in a powder experiment - the 3D diffraction information that enables one to determine absolute configuration is lost in this process.
Jeremy Karl Cockcroft On 14/11/2007, Franz Werner <[EMAIL PROTECTED]> wrote: > Dear Rietvelders > > Is it in principle impossible to determine the absolute structure from powder > data due to reflection overlap or is there a way via multiple wavelength > diffraction experiments? > > Thanks for your advice. > > Regards > Franz Werner > -- > Psssst! Schon vom neuen GMX MultiMessenger gehört? > Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger > -- Dr Jeremy Karl Cockcroft Department of Chemistry (University College London) Christopher Ingold Laboratories 20 Gordon Street London WC1H 0AJ +44 (0) 20 7679 1004 (laboratory) +44 (0) 7981 875 829 (mobile) [EMAIL PROTECTED] http://img.chem.ucl.ac.uk/www/img.htm or 6 Wellington Road Horsham West Sussex RH12 1DD +44 (0) 1403 256946 [EMAIL PROTECTED]