I am just entering into this subject . I have seen different XRD data without supplying the value of wavelength of X-RAY used . Is it that the value of wavelength is implied? One XRD machine always uses the same wavelength or it is varied. What are the values of the wavelengths used for XRD ? Can anyone supply me two XRD patterns of pure alpha iron obtained by two different X-RAY wavelengths ?
Respected Sir,
Generally, copper-K-alpha (1.54056 Ang) source is used to evaluate the XRD pattern in general laboratories. The wavelength is machine dependent. However, in the synchrotron, XRD pattern can be evaluated at different wavelengths. It is worth mentioning that similar to Co, Fe exhibit high fluorescence near the copper-K-alpha wavelength. As a result, the background (noise) of the XRD pattern enhances. Hence, it is convenient to use silver-K-alpha ( 0.56 Ang) line for Fe. We can easily generate XRD pattern at different wavelengths from a given data using Bragg's law.
I use to discuss about XRD with my friend Subarna Das perusing PhD in experimental Condensed Matter Physics. Please inform me if any other information is required.
Thanking You,
Your obedient student
Arka
Dear Arka, which data is needed to generate diffraction pattern at different wavelengths ? Do you mean generation by software or by real time experiments ?
Love and Regards
Nityananda Das
Respected sir,
We can get wavelength dependent XRD pattern (real experimental data) using synchrotron (not very easy to avail). However, using programs (or JCPDS data base) we can get the frequency dependent patterns theoretically. Another thing is that, if we know the system, and the hkl indices of a different peaks of a XRD spectrum at a given wavelength. We can calculate the corresponding spacing of planes (d value). From the peak position we can get the theta value. Thereafter, we can use 2d sin(theta)= n lambda. To get different theta for different lambda.
Thanking you,
Your obedient student
Arka.
Dear Arka
My question is in opposite angle. Think I have an XRD pattern and the wavelength of the X-RAY is supplied and nothing more. Can we identify the material and the crystal structure of this material ?
Love and Regards
Nityananda Das
Respected Sir,
Rietveld can solve the purpose. There are some softwares available for this eg fullprof, Maud, jana2006 etc.
Otherwise, comparing the spectrum with database we can identify the elements. But this is not very easy process.
Thanking you,
Your obedient student
Arka
Dear Arka
Thank you for your valuable response and providing the sofwares to be used .
I think these softwares are not affordable . I don't know.
Love and Regards
Nityananda Das
Dear Doriana
Your answer is helpful. I want to study on an alloy of mixture with different percentage of mixing. So is it possible to get how the pattern changes with variation of percentage of mixing? Giving an example of already done material, say mixing of carbon with Ee. Can I get the explanation of the variation of XRD pattern with the variation of carbon percentage ? Can you help me , please. This is on one hand on my research interest , on the other hand for teaching purpose.
Regards
N Das
Respected Sir,
These softwares are completely free. Rietveld is very popular and important for XRD. We can obtain many informations about the crystal.
Thanking you.
Your obedient student
Arka
Dear Doriana Vinci
Thank you very much for your answer. Sole idea of my work is not to study the variation of XRD pattern with variation of carbon. Rather I want to verify the theory by simulation and then prepare some sample and ultimately the study of different material properties.
Regards
Nityananda Das
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