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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36 views

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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39 views

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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166 views

Structure factor of crystals (X-ray crystallography)

How can one prove that the degree of each node in a distance graph must be at least four in order to obtain a unique solution to an exact distance geometry problem with sparse distance data? The ...
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28 views

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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392 views

Bragg diffraction and lattice planes

Crystalline substances show, for certain sharply defined wavelength and incident directions, very sharp peaks of scattered X-ray radiation. From the illustration below we see that we get constructive ...
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39 views

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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46 views

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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32 views

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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30 views

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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27 views

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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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 ...
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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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49 views

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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23 views

Occupancies of atoms in a crystalline structure from wyckoff positions of space groups

I am trying to fit an XRD pattern using the ILL program: FullProf and in one of the codes I have to enter the positions and occupancies of the atoms in the unit cell. I am working on the YSZ ($Y_xZr_{...
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45 views

Space groups and crystals. Simple example for the diamond structure

I try to learn the basis notions in crystallography and space group. But I already fail at the beginning. Let me give you an example: Consider the diamond structure (space group $Fd\overline 3 m$, ...
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52 views

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 ...
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42 views

Any freeware or shareware (demo/evaluation version) software to peak match XRD precalculated pattern?

I have an XRD data with an already calculated pattern from another analysis software and I need to peak match this pattern to XRD database. Is there freeware or shareware to do it. I tried crystal ...
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53 views

Help understanding and reading atomic positions of crystals

I am familiar with both Cartesian coordinates and fractional coordinates of crystals. However, I am having trouble reading the atomic positions that are listed in some research papers. For example, ...
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30 views

Structure Factor for a Simple BCC Lattice

This is an example of a general misunderstanding I am having. The structure factor is given by $$S=\sum_{j}f_je^{i\mathbf{G}.\mathbf{x_j}}$$ where the index $j$ denotes a sum over the atoms within a ...
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45 views

Process of x-ray crystallography

This is a pretty basic question but I would just like some confirmation of what I suspect is true. As I understand it, the basic idea behind x-ray crystallography is that we take our crystal and hit ...
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16 views

Which crystal defects might single, very bright Reflexes in Laue Images indicate?

In a Laue X-ray crystallography , if you observe a single Laue reflex very bright, which is not one of the main reflexes, can that indicate a certain crystal defect or is it a peculiarity in the ...
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8 views

Position in reciprocal lattice (for Triangular real lattice) to find photonic gapmap

To find Gap-Map, using FDTD, for square lattice of dielectric coulumns in air, I choose the 'X' position in reciprocal lattice, while varying the radius of the rods. The result is good. But while ...
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44 views

Sum rule in X-ray Photoelectron Spectroscopy (XPS)

What is the sum rule in X-ray Photoelectron Spectroscopy (XPS)? how can I derive it? Can anybody explain the principle of sum rule in XPS or in spectroscopy in general? How can I apply it to a ...
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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 ...
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45 views

How do atoms scatter X-rays?

I am learning the theory behind X-ray diffraction but I have a question. According to the textbook I am using, X-ray tubes (in diffractometers) produce near monochromatic X-rays. In other words, they ...
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44 views

How can we prove that each point (hkl) in the reciprocal lattice corresponds to a set of lattice planes (hkl) in the real space lattice?

In crystallography, we always speak about the direct and reciprocal lattice spaces. One property about these spaces in mentioned here, as follows: Each point (hkl) in the reciprocal lattice ...
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105 views

Space group setting of a crystal structure

I was reading a PDF of a crystal phase in order to draw its structure, when I noticed that it was, apparently, ambiguously described. The PDF lists two descriptions of the monoclinic structure: 1) ...
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1answer
64 views

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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29 views

About X-ray Dynamical Diffraction

I am studying X-ray Dynamical Diffraction. I understood that X-ray Dynamical theory is used when higher-order scattering or multiple scattering terms in the Born series become important and cannot be ...
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39 views

Can the hole concentration of cuprate superconductors generally be determined from lattice parameters?

As it is known, in YBCO superconductors, lattice parameters are strongly dependent on hole concentration, so hole concentration can be determined by measuring the c-axis parameter, see e.g. "Oxygen ...
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2answers
474 views

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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271 views

Compute distance between planes in a crystal

I want to compute the distance between two (111) planes in a cubic crystalline structure, in order to do some computations involving Bragg reflection. I have a sketch of which the (111) planes are, ...
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435 views

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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Iron-carbon bistable structure

I have just extracted the metallic inner part of a safety wristband (a bi-stable structure), and performed an EDX analysis. I found that it is composed of $Fe$ ($86$ wt%) and $C$ ($5.5$ wt%) and $O$ ($...
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99 views

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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143 views

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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1answer
228 views

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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1answer
51 views

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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1answer
67 views

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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68 views

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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22 views

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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1answer
93 views

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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209 views

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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1answer
49 views

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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2answers
56 views

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 ...
2
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1answer
84 views

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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767 views

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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146 views

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 ...