XRD data: particle size, cell size etc

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Discussion Overview

The discussion revolves around the interpretation of X-ray diffraction (XRD) data, specifically focusing on changes in peak positions, intensities, and widths as temperature varies. Participants seek to understand how to calculate particle size and unit cell size from the data collected during heating and cooling cycles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant observes that XRD peaks shift to the right with increasing temperature, intensities decrease, and peak widths increase, prompting a request for interpretation of these phenomena.
  • Another participant suggests using GPDS cards or a handbook to determine Miller indices from the XRD pattern, indicating that this involves matching observed peak angles to known data.
  • A participant expresses a desire to calculate unit cell parameters directly from the recorded intensity vs. 2*theta data without relying on unit cell parameters already known.
  • Questions are raised about the implications of the observed shifts in intensity and peak positions with temperature changes, seeking clarification on their significance.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the interpretation of the XRD data or the methods for calculating particle and unit cell sizes. Multiple viewpoints and approaches are presented, indicating ongoing exploration and uncertainty.

Contextual Notes

Some assumptions about the relationship between temperature and XRD peak behavior are not explicitly stated, and the discussion does not resolve the mathematical steps necessary for calculations.

Who May Find This Useful

This discussion may be of interest to researchers and students working with X-ray diffraction data, particularly in materials science and crystallography, who are looking to interpret temperature-dependent changes in XRD patterns.

Oxygenne
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I use to do XRD from room temperature to High temperature and then cooling again at room temperature.
I see there is constant going to the right for all the peaks and also their intensities are decreasing, also the width of peaks is becoming larger.
I would like to interpret those data and also to calculate the particle size and the unit cell size (if there is a change with the temperature).
It seems the phase is not change only the garbages and the intensities values.
Could you help me to interpret those data or to guide to read something on the web to help me with this?
Thank you!
 
Last edited:
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Thank you drizzle!
On an Intensity vs. 2*theta plot of a powdered, crystalline sample how to calculate the miller indices?
 
I think to determine the miller indices of each peak [the surface where the diffraction occur] you would need to use GPDS cards or a handbook [it’s a catalogue that holds the analyzed XRD data of almost all structures and compounds, will maybe not all, it depends on the book]. it goes like this; in your XRD pattern you would see several peaks, each at a precise angle. say that your XRD pattern is of the material ZnO and the first peak is at 35 degrees, you then should look for ZnO in that data and find the matched angle thus the corresponding surface, you would find tables of different data, i.e.

XRD pattern for ZnO:

(hkl) 2θ relative intensity
100 35° 87.5
102 47° 63
etc

also it could be calculated.
 
I would like to calculate taking in account the data I have (Intensity vs. 2*theta plot)

I found a formula but there is included the unit cells parameters and I do not want to use that, because my goal is to find the unit cell parameter using the recorded data for each set of data.

* How to interpret the constant moving of my intensities to the right with each temperature step?

*How to interpret the constant decreasing in intensity of every peak with each temperature step?

Thank you!
 
Last edited:

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