Crystallinity index= Max intensity-Min intensity/max intensity and Debye Scherrer equation, D=Kλ/β Cosθ
Scherrer eqquation not Debye-Scherrer for g** sake! I would love to know who has spread the "Debye-Scherrer" name. It seems quite common in India, so there should be some text there written by somebody who did not know what he was writing!
The answer to your question is however easy: you can't relate them just based on diffraction data. At most you can say that particles are at least as large as the crystallites (that are actually the coherently scattering domains).
Scherrer eqquation not Debye-Scherrer for g** sake! I would love to know who has spread the "Debye-Scherrer" name. It seems quite common in India, so there should be some text there written by somebody who did not know what he was writing!
The answer to your question is however easy: you can't relate them just based on diffraction data. At most you can say that particles are at least as large as the crystallites (that are actually the coherently scattering domains).
If you measure scattering at low angles (SAXS), this will give you information on both particles and crystallites (size, shape, distribution, clustering) between length scales of 1nm to 10 microns. The Scherrer equation is not an accurate method for measuring even average crystallite size.
If the particles have homogenous size and shapes, you can (possible) have a regular change in crystal size related to particle size. However, the values for crystal sizes are not the same for the particle sizae
To make it clear, Particle size always (at least) greater than the crystal size. The information you get in XRD, all related about the crystals like size, plane and orientation. Moreover there are specific technique to decipher the materials structure in XRD. Recently Scherrer equation has many version to make the obtained value is reliable. I suggest to the refer modified Scherrer equation and also Williamson Hall method to calculate the crystal size. Both give reliable answer.
Shivani! You ought to at least edit the original query and fix it. You are from the great Birla Institute (BITS Pilani) after all :-)
"It seems quite common in India" - Actually NOT! The ailment seems to have come from elsewhere but has certainly spread across the continents. I was schooled in India in the seventies and had no such misconceptions between the Debye-Scherrer camera and the Scherrer equation. There are no standard texts that confuse the obvious in India or elsewhere. In my opinion, it is only a Freudian (not Indian) slip. Perhaps, some folks mistakenly consider Debye as Scherrer's fist name? It is Paul! :-)
This affliction seems to be an equal opportunity paradigm. Certainly seems to be a common notion among several RG members despite vociferous apprehension from expert members. These perpetrators are not, have not and don't intend to read and pay heed to voluminous futile pontification regarding this universal scourge :-)
If you have any pride in your XRD knowledge then RECANT, CONFESS and ATONE for such transgression no matter what your ethnic origin may be. Resolve never to confuse the Scherrer equation for estimating the diffracting domain size with the Debye-Scherrer camera employing a cylindrical film with rotating powder sample in a capillary (or other means).
BTW, just to add some political spice, it could also have been because there is an Italian named Sonia Gandhi that was running the show in India in the past after I moved out? :-)
Can't find photo of Debye yet! What is the first name? Incidentally, Paul is a tough looking character. His grad students must have been petrified of him :-)
https://www.physics.wisc.edu/undergrads/courses/spring2016/407/experiments/xray/Powder.pdf
https://en.wikipedia.org/wiki/Paul_Scherrer
https://en.wikipedia.org/wiki/Scherrer_equation
https://en.wikipedia.org/wiki/Sonia_Gandhi
Ravi Ananth
Peter Debye. I'm sure you must have known this! Lots of pictures:
https://en.wikipedia.org/wiki/Peter_Debye
Another famous individual who studied under Sommerfeld. See also:
The life of Gustav Mie and the development of the Lorenz-Mie solution to Maxwell’s equations http://tinyurl.com/mt97tp3
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