is it correct that mesoporous structures gives large XRD peaks in small 2 theta ranges due to the regular arrangements of porous channels and cages ?
If the sample is mesoporous, but XRD peaks are normal. What could be the reason?
Hi!
Do you like to say that the sample is mesoporous, but XRD peaks are normal, but in which range of two theta, either small angle range to very small range or high angle ("normal") range. The question is to distiguish what scatters: is it diffraction, based on coherent atom scale scattering, or SAXS in which scattering entities have a much larger extend?
Regards
Daniel
Thanks for the reply.
Actually, the diffraction based on coherent scale scattering.
Picture is attached here for your kind consideration. Please help
This looks a perfect XRD of well crystallized material (with probably high symmetry). The question of mesoporosity does not rise from this pattern. Please proceed to SAXS analysis if you would like to know more about the "impact" and organisation of the pores, which have been evidenced parallel, I suppose.
Regards
Daniel
Let me remind you that the reflexes in the XRD are associated with long-range order of atoms arrangement (!!!). Low-angle scattering gives information about short-range order, but of atoms again.
If you approach formally, compare, please, the wavelength of XRD with the expected period of the location of the pores (see Ravi Ananth answer). It is also easy to calculate the angle at which such reflex will be located. It will be extremely small, i.e. as minimum out of range, you showed on image. Although I very much doubt in the existence of a periodic arrangement of pores. Such pore arrangement may be seen by electron microscopy, and may be even by optical one ...
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