why xrd data of powder materials do not have stable baseline throughout 2theta range(10-90) . Baseline shifts from top to down as angle increases?
Dear Nalinee,
for the x-ray energies used in XRD the elastic (also called coherent) scatter of x-ray dominates (compared to Compton scatter).
The elastic scatter cross-section decreases with increasing scatter angle via (1+cos²theta). This holds for all x-ray photons collected in an XRD pattern, the XRD peaks, which additionally are caused by interference phenomenon as well as the background.
Please have a look at the first sentences of the link.
http://xdb.lbl.gov/Section3/Sec_3-1.html
Dear Nalinee,
for the x-ray energies used in XRD the elastic (also called coherent) scatter of x-ray dominates (compared to Compton scatter).
The elastic scatter cross-section decreases with increasing scatter angle via (1+cos²theta). This holds for all x-ray photons collected in an XRD pattern, the XRD peaks, which additionally are caused by interference phenomenon as well as the background.
Please have a look at the first sentences of the link.
http://xdb.lbl.gov/Section3/Sec_3-1.html
It also depends on the support of your analysis : is it plastic or glass ? Plastic creates a broad, but with low amplitude, modification of the baseline.
Dear Nalinee Suryawanshi
Have a nice day
X-ray diffraction pattern of powder materials do not have a stable baseline throughout 2 theta range(10-90). The baseline shifts from top to down as the diffraction angle increases, this is attributed to many factors:
1- The distribution of the powder's atoms through the measured sample.
2- The variation or the non-homogeneity of the crystal structure of the investigated sample, where the sample sometimes contains a mixture of crystalline, partial crystalline and amorphous particles.
3- The calibration of the X-ray apparatus itself.
4- The applied energy and electrical current.
5- The rate of scanning.
All these parameters affect of the obtained XRD-diffractograms.
Thank you,
Yours Ahmed
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