Dear all
How can texture in a powder sample be modeled in ARTEMIS?
I am not sure that it can be. EXAFS is sensitive to local structure around the absorbing atom and is not sensitive to crystallinity or long range order. Well, EXAFS *is* sensitive to the relative orientation of the local structure to the polarization of the incident X-ray beam (usually horizontal unless you're purposely changing the polarization, but since you didn't mention this, I'll assume you are not doing this).
My samples are fine powders of a layered material, mixed with cellulose and pressed to pellets. The data were collected in fluorescence mode with a 45 degree tilt.
PXRD data reveal that the samples are highly textured, including standards.
My understanding is that texture in powder diffraction reflects a limited range of orientations in a sample, insofar as there may be preferential ordering and an incomplete distribution of orientations. But crystal orientation and local structure are not necessarily the same thing. If the texturing means some interatomic bonds are preferentially oriented with respect to the horizontal plane then maybe there would be an effect. But that more or less requires the local structure (not the crystal structure) to be anisotropic around the absorbing atom. That is, even if the crystal is a layered material, if the absorbing atom has an isotropic environment, there will likely be very little or no effect.
On the other hand, if the structure is layered and those layers are preferentially in the horizontal plane, then EXAFS will be preferentially probing bonds along the layer planes.
Sorry if that sounds too vague, but I cannot give a more specific answer without knowing more about the system. Maybe someone else here can.
--Matt