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+ Electron
+ X-ray reflectivity
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Ajay Kumar

Calculating critical angle density XRR?

Bob  Follow

That helps thank you.

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Caren McElrea  Follow

The electron density should be changed into "electron number density", which means the number of electrons in the unit volume. For example, the atomic number of Si is 14, and the number of atoms in the unit cell is 8. The unit cell volume of Si is (5.43A)^3. Therefore, the electron number density is ~0.7 electrons / A^3. 0.007 looks so small. Moreover, "θc ≈ sqrt(δ)" should be changed into "θc ≈ sqrt(2*δ)".

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Doctor Lee  Follow

Dear Muneeb Ahme ,
I do not know from where you fetched your formula.
Please see the relations to calculate the critical angle at page 8 of:

Presentation Attenuation Length and Penetration Depth of X-rays

They were picked up from the Parratt paper, the details of which are given on page 9.
I will send you this paper.

By the way: pay attention; yours and the 'Parratt' formula will give the angle in radians, but not in degree...

Please convert accordingly
θc[deg] = θc[rad]*180/pi
180/pi ~ 57,3; that might be the factor you are missing...

Best regards
G.M.


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