X-ray crystallography encompasses the structural characterization of crystalline materials by means of X-rays. This is done most commonly by X-ray diffraction, which can be applied to monocrystalline materials or heterostructures, as well as to polycrystalline materials, where the later is referred to as powder X-ray diffraction.
Questions tagged [x-ray-crystallography]
244 questions
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Why do quasicrystals have well-defined Fourier transforms?
I was recently reading about quasicrystals, and I was really surprised to learn that even though they do not have a periodic structure, and only have long range order in a very different sense to the usual one, they can still be detected via…
Emilio Pisanty
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Why is $K_{\alpha,3/2}$ always more intense than $K_{\alpha,1/2}$ in copper?
Consider characteristic X-ray emission from copper. The $K_{\alpha}$ line is a doublet because of the spin-orbit interaction.
But why is the $K_{\alpha,3/2}$ line always more intense than the $K_{\alpha,1/2}$?
Sørën
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Distance between adjacent planes in a crystal
This question has been asked before, but there doesn't seem to be a decent answer.
Many sources state that " For cubic crystals with lattice constant a, the spacing d between adjacent (ℓmn) lattice planes is:
$$ {\displaystyle d_{\ell mn}={\frac…
user57927
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8
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What exactly is the reciprocal lattice and how is it connected to the Ewald sphere?
I want to understand what the reciprocal lattice is and how it is connected to the Ewald sphere.
I know a very similar question has been asked on this site already: Reciprocal lattices. The top answer states:
...The reciprocal lattice is simply…
qmd
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Calculating diffraction patterns using FFT
I'm trying to write a piece of code that calculates a diffraction pattern similar to an X-ray experiment using a FFT.
From my knowledge, the diffraction pattern for point particles can be calculated from the following formula:
$$
S(\mathbf{k}) =…
user1294203
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How to determine the degree of how high a symmetry of high-symmetry points in the first Brillouin zone?
For exmple, we have a hexagonal lattice with hexagonal Brillouin zone, shown in the picture
The points $\Gamma$, K, M and $\Lambda$ are high symmetry points. Now, $\Gamma$ point is the highest-symmetry point, while others are high-symmetry points…
Capo Mestre
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Why are X rays in X ray crystallography diffracted by the electron clouds rather than nuclei?
I am considering the nuclei as solid particles and the electrons as waves creating clouds of electron density around the nuclei. Thinking of it like this, I can't see how X rays are diffracted by the electron clouds and not nuclei. Perhaps I am…
Meep
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Can X-ray diffraction be applied to liquids, gasses or non-crystalline materials?
I learned that X-ray diffraction happens due to the periodic arrangement of atoms in a crystalline material, so can X-ray diffraction studies be done on liquids and non-crystalline materials?
theenigma017
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Interplanar distance in FCC and BCC
Interplanar cystal spacing of cubic crystal families is defined as
$$d_{hkl} = \frac{a}{\sqrt{h^2+k^2+l^2}}.$$
This source says that the interplanar spacing of the $(111)$ plane in FCC is $\frac{a}{\sqrt3}$, which is in agreement with the formula…
sendilul
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How are X-rays focused? Specifically in XRD. Well do they even focus X-rays in XRD?
I read in a government website that reflecting an x-ray from a parabolic mirror followed by a reflection from a hyperbolic mirror results in focusing the x-ray, but this was for astronomical purposes. I was wondering if in x-ray diffraction this…
user17338
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Medical X-Ray - why no diffraction?
When I go to a doctor and he wants to see my bones he uses X-Ray. My bones contain crystalline material called hydroxyapatite.
Why the result of imaging is the shape of my skeleton and not just XRD pattern of hydroxyapatite in my bones? Do they use…
user46147
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Lattice parameters and basis vectors of crystal lattice structures
Does someone know where I can find lattice parameters and basis vectors of crystal lattice structures (Strukturbericht Designation) for different materials?
In particular I am searching the lattice parameters and the atomic basis of the…
thyme
- 1,453
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3 answers
X-ray diffraction analytical principle - diffraction or reflection?
I am an MSc in analytical chemistry, currently working with x-ray diffraction.
The technique is called "x-day diffraction", but are not the x-rays reflected? Max von Laue discovered that x-rays were diffracted by the crystal lattice, but the Braggs…
Yoda
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How many atoms does one need to get reliable crystal information with X ray or electron diffraction?
I know that, in theoretical derivations of X ray diffraction (XRD) or electron diffraction (ED), we always assume an infinite lattice, and, as you make the crystal smaller, edge effects start to matter more.
As you make it even smaller, you start to…
YungHummmma
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1 answer
Why does Bragg's law consider only specular scattering for constructive interference?
My textbook only considers two-dimensional scattering, so I will stick to that. When explaining Bragg's law, it states that the incidence angle and the scattering angle must be equal so that all trajectories from different atoms (from the same row)…
TheScientist
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