# Tagged Questions

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 ...

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### X-Ray diffraction - Braggs law

"Based on the Bragg equation, if crystal A has larger spacing in its diffraction pattern than crystal B, what conclusion can you draw about the spacing between layers of atoms in A compared with B?" ...
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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 ...
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### What is the current status of the field of quasicrystal?

So this is a soft question. I am just wondering what is the current status of the field of quasicrystals? Does this kind of material have any real life application? Is it a possible playground for ...
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### How to convert intensity arbitray units to percentage in a XRD data?

In powder x ray diffraction result contains mainly two values 2theta and intensity where 2theta is in degree's and intensity is in arbitrary unit ...
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### Spot intensity in x-ray-crystallography

In x-ray crystallography why is it necessary to oscillate the crystal by a few degrees to get proper spot intensities?
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### What are some resources for learning about x-ray powder diffraction?

I am looking for up-to-date, applied resources to learn about x-ray powder diffraction. There is a lot of jargon with which I am unfamiliar. I am trying to refine theoretical curves to collected data ...
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### Why is the X-ray diffraction useful for studying the structure of nucleic acids?

It is well known that the double helix structure was determined by the X-ray diffraction method. But it always baffles me. DNAs are not simple crystals. They are not periodic, not at all. So how ...
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### High pressure deformation of metals

Does copper undergo elastic recovery after being exposed to high pressures (above 30 GPa in a diamond anvil) at room temperature?
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### X-ray Diffraction: Difference between characteristic radiation peaks and diffraction peaks (hkl)

I'm having hard time understanding the charasteristic X-Pay peaks. I have XRD data which I plotted in the figure below. I'm supposed to find the X-Ray tube material by finding the wavelengths of K-...
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### Neutron diffraction on Salty Ice VII

Can someone explain in layman's term how this figure shows the presence of Cl and Li ions in Ice VII ? What can we deduce about the crystal from this data ? The whole figure and caption are ...
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### Why long range ordering and higher order rotational symmetry leads to dense K-space ?

In case of Quasicrystals Why long range ordering and higher-order rotational symmetry leads to dense K-space ? And high rotational symmetry include modification in discrete spectral feature to ...
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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 ...
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### Reciprocal Lattice in Crystallography

How do you get the reciprocal lattice vectors? No, I'm not talking about the formula's. I mean to ask where do the formula's even come from? I could not find a clear derivation of the reciprocal ...
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### x-ray diffraction of crystals

In explaining x-ray diffraction of crystals, usually the approach is to consider the atoms absorb radiation and scatter it, at some angles constructive interference occur and bright spots can be ...
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### X-ray diffraction on thin film

As far as I am concerned, when we perform an X-ray diffraction experiment using a Bragg-Brentano diffractometer using the "powder method" we have that the scattering pattern depends on only one angle ...
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### Is crystal diffraction actually diffraction?

It seems like a very common model that is taught in schools for crystal diffraction is that there is an incident plane wave of light on a crystal lattice, and each atom in the lattice scatters the ...
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### How are lattice parameters determined from reciprocal space maps?

It seems that the papers speak of reciprocal space maps with very high praise because of its ability to study strain in epitaxial films and determine the amount of relaxation. Also one can determine ...
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### Four dimensional Bravais lattice

I am wondering if there are any reference on four dimensional Bravais lattice and their primitive vectors, even an example will help.
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### What is the reason that EXAFS are done with monochromatic x-ray light?

Why is the light incident on the samples in EXAFS experiments monochromatic? What would happen if a broad bandwidth hits a grating and then all the diffraction spectrum goes through the sample and is ...
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### Does the EXAFS oscillations occur when ultrashort x-ray pulse is used? Electron with a 50eV kinetic energy will travel in 0.1fs 4.2 Angstroms

In X-ray extended absorption spectroscopy (EXAF) an electron is excited by an x-ray photon into the continuum, the outgoing electron wave interferes with the scattered electron wave from the ...
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### Getting the ($hkl$) Miller indices from the angle of incidence of a light ray

I was given an X-ray diffraction lab this week. We measured the count rate for different angles $2\theta$ of the rotation of the detector. From these measurements we plotted a graph of 2theta vs the ...
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### How to identify a crystal structure by its x-ray reflection bragg angles?

How to identify a crystal structure by its x-ray reflection bragg angles? Suppose we have a crystal sample to examine its crystal structure (e.g. SC, BCC, FCC, etc). What we can get from an X-ray ...
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### Software to calculate and visualize reciprocal lattice

I am currently preparing XRD experiments for an epitaxial thin film on a silicon wafer. I am looking for software (Win oder Mac) to calculate the reciprocal lattice from the cell parameters and ...
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### Understanding Braggs x-ray diffraction and why light is treated as a single “ray/line”

I'm not familiar with optics. So my knowledge of treating light as single lines is almost completely foreign to me. Although I do know something about EM waves and Maxwells equations, so you can ...
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### What is an off-axis peak in x-ray diffractometry?

I'm looking at a $\theta$ - 2$\theta$ pattern of my thin film which in bulk is cubic (bcc) and I see 001 and 002 peaks of the film. There is supposed to be a tetragonal distortion meaning that I need ...
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### Are the 14 Bravais lattices really distinct?

I have learned that there are 14 distinct Bravais lattices in 3D and any other thought lattice form could be reduced to or expressed in one of these 14 forms. But the primitive unit cell for f.c.c ...
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### Zero Diffraction Plates: Why do they give such low diffraction signals?

In our laboratory we use silicon plates named "Zero Diffraction Plates". They are named so because they give extremely low diffraction signals in an XRD instrument (reflection mode). But how are these ...
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### Why can the twin plane be uncoincide with the composition plane in reflection twin?

In the book Elements of X-Ray Diffraction, p67, I found the following sentence: In the case of a reflection twin, the composition plane may or may not coincide with the twin plane. But I think ...
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### Is it more difficult to create higher energy photons, given there is excess available energy?

Im not talking about pair production, I mean a single photon created from an energy transition between two electron shells. I'm studying K(alpha) and K(beta) fluorescence transitions in metals, and ...
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### X-ray diffraction analyisis: The angle of elastic x-ray scattering

What is the scattering angle distribution for x-rays (in the 8keV range) scattered elastically? I work with XRD analysis, which is fundamentally basede on these elastic scatterings of x-rays. I read ...
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### 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 ...
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### The reciprocal lattice of HCP lattice

There is a very similar question here Reciprocal Lattice of a non-bravais lattice, but I don't fully understand the answer, and the question is now obsolete so I feel that I should ask it again. How ...