Dear All,
I have a philosophic question for you: the structure obtained by NPD are
better than the ones found by XRPD?
I explain a little bit more my question, I studied a MgAlFeO4 spinel both by
NDP and XRPD from RT to 1000°C. The O coordinate it is different for two
data set (0.2581
The advantage of neutron powder diffraction is that the scattering power
of light atoms like oxygen is as great as for heavy atoms; for X-rays, the
heavy atoms dominate, so errors for the light atoms will be greater. A
second advantage is that with neutrons you have a larger sample, so a
better
Hello,
do not mind statistical precision (your error at the oxygen coordinate)
and look at the errors (e.s.d.) of the interatomic distances, especially
of those between bonded atoms. Precision of CW neutron machines is
frequently not so high as X-ray diffractometers, but this problem is
Davide,
Did you check for extinction and preferred orientation? Otherwise what
does a combined fit give? The difference of about 10 sigma suggests a
remaining systematic error. What is the impact of refining anisotropically?
Good luck,
Jon
Davide Levy wrote:
Dear All,
I have a
Davide,
Could you perform Rietveld refinement using combined neutron and x-ray data?
This would increase accuracy and the question what is better would
disappear. Basically all you need is both data done at the same temperature.
Also look at neutron and x-ray scattering factors. The neutron
I have a philosophic question for you: the structure obtained by NPD
are better than the ones found by XRPD? I explain a little bit more my
question, I studied a MgAlFeO4 spinel both by NDP and XRPD from RT to
1000°C.
Rather than continue to discuss philosophy, the following paper seems
Hi,
To what has already been said I think the two round-robin articles are a
must-read about this issue, as they compare refinement of neutron and X-ray
data for a given (simple) compound. They are a bit old, especially by today's
synchrotron standards, but are still very interesting
