Did anyone look into the effects of using circularly polarised x-rays?
Just wondering...
Jon
Larry Finger wrote:
Franz Werner 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.
To determine absolute structure, you need three things: (1) a
non-centrosymmetric structure, (2) at
least one "anomalous" scatterer, and (3) the differences in intensities between
Friedel pairs of
reflections, i.e. reflection hkl and reflection -h-k-l.
In any diffraction experiment with the wavelength chosen carefully, you could
satisfy conditions 1
and 2. Number 3 always nails you in a powder experiment due to the systematic,
exact, overlap of hkl
and -h-k-l.
Larry
