I am working on polymorphs of organic materials. We used to compare the PXRD patterns of two/more polymorphs in the PXRD overlay. This is used to differentiate the polymorphs as they have have different conformations and hydrogen bonding networks in the crystal structures. Now I want to know any other informations we could able to tell from PXRD patterns?
I suggest you post your data to make it interesting and get better insight from experts. I'd also suggest using all the five topics allowed by RG to share this question. Spread it around. Think "out-of-the box"!
PXRD - Powder XRD? Is that your sample morphology? Powder? Or do you mean the technique only?
http://www.flickr.com/photos/85210325@N04/10659886546/
Here is an example of a real time PXRD for LaB6 standard from BNL. What do you see from the real time data as the powder sample is rotated about the Synchrotron beam?
In your case most likely you mean the conventional 1D (Linear) equatorial diffractogram with 0D detector. Correct? Well, this is a compressed version of the 2D diffraction image. The following image will illustrate the effect of this compression (also known as convolution or integration). This essentially would be the result of such reduction of 2D data in to 1D (polar integration - r, theta):
http://www.flickr.com/photos/85210325@N04/8614015417/
YouTube Video "Transmission Laue" LaB6: http://www.youtube.com/watch?v=acgFl5M7P-I&list=PL7032E2DAF1F3941F
Please note all mention of Lanthanum Hexaborate should be Lanthanum Hexaboride. I'm sure you are aware that you may turn off the ads for sure on YouTube and the music if you choose to. There is no other audio presently. The data is self explanatory and there are some annotations being improved up on. I'll walk interested parties through with pleasure!
Your feed-back would be appreciate to improve.
http://www.flickr.com/photos/85210325@N04/7890468142/in/set-72157632724090465
Thank you for the link. But I mean the PXRD is a technique in my question. We have here powder X-ray diffractiometer and so I want to know any other information like any properties can be extracted from powder x-ray diffraction pattern of powder materials. I have gone through the link you mentioned that was micoscope. Any other information you have about diffractometer please share.
I suggest you read some fundamental books on XRD to understand the scope for PXRD. In short, it is the simplest but one of the most elegant methods of peering directly in to the reciprocal space. The conventional method involves the rotation of the sample (ala Debye-Scherrer camera) to get the average parameter for the powder. With modern 2D detectors there is no need for this conventional "smudging" process. Individual intersections of the Ewald sphere and the diffracting vector may be recorded and later integrated if necessary. A similar method was used by Dr. Sigmund Weissmann et al @ Rutgers to deconvolute the Nano structural details of individual particles in the "powder" (aka the XRD rocking curve method). Of course, one would need to use this with larger particles or use system divergence to create magnification. This usually works for large particle sizes (10+ microns) not for Nano powders for now. Once the 2D area detector's resolution improves, all bets are off!
In general these are some of the Nano structural parameters quantifiable with the conventional PXRD method:
1. Bragg Peak Positions & Relative Intensities: For randomly oriented powders this information would yield the structure factor details controlled by the chemistry and molecular morphology of the materials.
2. FWHM: Could be used to determine the coherently diffracting domain size along any diffraction vector. There are many conventional numerical methods incorporated in to software tools such as the Reitveld analysis, the Warren-Averbach analysis, Rachinger correction etc. that would improve the resolution.
3. Preferred orientation: It is also feasible to determine the preferred orientation in the powder (or bulk) using PXRD. However, it would be time prohibitive to achieve this using the conventional 0D point/scintillation detector system.
4. I consider PXRD to include SAXS & WAXS. So depending on how close you can get to Zero degrees 2-Theta, you may be able to get a lot more data about the Nano structure of your sample. The periodicities you will be able to quantify would be inversely proportional to the 2-Theta. Meaning, the larger periodicities towards the lower 2-Theta. You can affect the resolution in reciprocal space by changing the variable on the ordinate axis (2-Theta). You may experimentally do so by changing the incident beam wavelength through tube target selection. The extinction depths would alter as a result as well.
5. Nano structural resolution would depend on optics used and beam conditioners utilized. Incident beam characteristics including wavelength/geometric dispersions.
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6. Other....
More relevant links (join and share):
a. Historical perspective of XRD:http://www.linkedin.com/groupItem?view=&gid=2683600&type=member&item=231584534&trk=groups_search_item_list-0-b-ttl&goback=%2Egmr_2683600%2Egde_2683600_member_5803264366392401921%2Egna_2683600
b. XRD resources: http://www.linkedin.com/groupItem?view=&gid=2683600&type=member&item=168811359&trk=groups_search_item_list-0-b-ttl&goback=%2Egmr_2683600%2Egde_2683600_member_5803264366392401921%2Egna_2683600
I'd encourage you to study and thoroughly assimilate the following book:
X-ray Diffraction In Crystals, Imperfect Crystals and Amorphous Bodies by Andre Guinier. 1962 - Great book! Worth acquiring for your XRD collection.
http://www.flickr.com/photos/85210325@N04/10515372183/
This is the information I am looking for. Thank you very much. I will find this great book for more understanding.
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