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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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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27 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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32 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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25 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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25 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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29 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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1answer
51 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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27 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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20 views

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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75 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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2answers
97 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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26 views

XRD and Superconducting Volume Phase

I have prepared H-Tc Superconductors polycrystalline samples. In the XRD pattern there is not extra peaks and we can say the sample is pure, without impurities. But SQUID shows that only 60% is ...
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150 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
56 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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236 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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25 views

How to determine film thickness in a multilayer sample

What is the mathematical derivation or formula to determine thickness of each film in a multilayer sample with the help of X-Ray Reflectivity technique?
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61 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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42 views

How to estimate the lattice parameter from a Debye-Scherrer diffractogram

The question is: In a Debye-Scherrer diffractogram, centers of maximum intensity were noted at the following angles with respect to the straight through position (all these angles are in degrees): ...
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1answer
45 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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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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71 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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146 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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2answers
306 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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34 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
39 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 ...
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1answer
78 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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92 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 ...
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73 views

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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1answer
28 views

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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1answer
52 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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2answers
474 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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759 views

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 ...
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1answer
38 views

Why Nitrides have internal polarization?

Why GaN has internal polarization? I know that in wurtzite crystal structure, the atomistic bonds are not equivalent and as a result there appears a net dipole and consequently a polarization. But ...
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171 views

How do I use MAUD for phase quantification of XRD data with AMCSD standards?

I'm a biologist with some raw powder XRD data of biominerals, need to quantify different phases, can't access commercial software or databases at the moment. Does anyone have experience with using ...
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72 views

Reciprocal space maps units

I have seen reciprocal space maps in different units. In some figures, it is represented in delta(l) delta(h) reciprocal space maps units. In some figures it is shown in Q(parallel) and Q(normal) ...
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132 views

What exactly are crystal planes and how do they reflect x-rays?

What exactly are crystal planes and how do they reflect x-rays? Are crystal planes real physical planes or just an abstract concept? What are these planes made of? If they are an abstraction, what ...
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85 views

Why does inelastic X-ray scattering probe the longitudinal dielectric function as opposed to the transverse dielectric function?

Light is a transverse wave. Therefore, light in the optical range (i.e. visible light) couples to transverse collective excitations of a material when measuring the optical conductivity for instance. ...
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2answers
71 views

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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1answer
172 views

Q range calculation

I did a neutron diffraction experiment and I need to figure out which Q range we used. How should I calculate it from the incident wavelength and the diffraction angle?
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1answer
39 views

Why do we still get sharp scattering spots with quasi-crystal?

In a quasi-crystal, there is no translational invariance. This means there is no delta-function in the Fourier transform. But to get a sharp scattering spot, we need a delta function. Physically, ...
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303 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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1answer
111 views

EXAFS (Extended X-Ray Absorption Fine Structure) question?

EXAFS (Extended X-Ray Absorption Fine Structure), core electron is excited to the conduction band. The oscillations in the absorption coefficient persist for 100s of eV after the edge. Taking ...
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1answer
57 views

Diffraction, wave length

I read that when we want to study the structure of a crystal we have to use an electromagnetic wave which has a wave length of approximately the distance between two consecutive atoms in the crystal. ...
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190 views

Pseudocubic unit cells: how to construct one?

I keep coming across the term pseudocubic unit cell while reading about orthorhombic perovskite structures. No clear explanation ...
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32 views

Number of reflections for BCC crystal [closed]

I need to calculate the number of reflections expected for the (110) and (200) plane of a BCC crystal. How would you do it?
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1answer
63 views

Electrons scatter light; x-ray diffraction

why accelerated electrons "scatter" light? From Yale's chemistry open class, the professor said when a light passes by an electron, it "pulls" the electron up and down, and emit radiation in all ...
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2answers
234 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, ...
18
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1answer
631 views

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 ...
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1answer
154 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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2answers
510 views

Is the thickness of a sample related to the intensity of x-ray diffraction?

I understand that in general if we're adding more planes of atoms (increasing thickness of sample) then the intensity would increase because we have more constructive interference. But isn't there a ...