Questions tagged [braggs-law]

Condition for the angles for coherent and incoherent scattering from a crystal lattice, summarizing the diffractive interference pattern dictated by the geometry of the lattice. Normally for Rayleigh scattering (elastic scattering) of X-rays off atom lattices; but also for scattered neutron waves from nuclei or by a coherent spin interaction with an unpaired electron.

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Bragg's diffraction in crystal lattice moving with velocity V

A beam of non-relativistic neutron is moving along positive x-direction with speed v impinges on crystal at rest at angle 45 degrees. The first Bragg maxima is seen at this angle. The crystal is then ...
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Why is Bragg diffraction small-angle for thicker layers and/or larger molecules or unit cells? And wide-angle for small or shallow crystals?

It is easy to find equations that quantify this on the internet, but not an explanation as to why... Also, does this apply to electrons and neutrons? Or just X-ray reflection/diffraction?
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Why does the scattering wave vector and reciprocal lattice vector have to be the same?

In Introduction to Solid state physics 8th edition by Charles Kittel. The scattering amplitude is defined as, $$F=\int dV n_G exp[i(\bf{G-\Delta k}).\bf{r}]$$ where G is the reciprocal lattice vector ...
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How does the point-like refractive pattern in the Laué diagrams emerge?

I understand the Laue condition (and the equivalent Bragg condition). I also understand the rotating-crystal method for analyzing crystals. But I have a hard time to understand why in the Laue method ...
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Why only even integers occur in reflection indices of $\rm KCl$?

I was reading kittel and came across this .Its mentioned that since scattering factors of k+ and cl- are almost same the entire crystal appears to be a simple cubic crystal of constant $a/2$. but how ...
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What is the interplanar distance? Bragg´s law [closed]

An X-ray (wavelength λ= 12.4 pm falls on a crystal) The incidence angle (Θ) is the same as the dispersion angle = 16.6 degrees. What is the interplanar distance if we observe the first order maximum? ...
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How to calculate a lattice constant from scattering electrons? [closed]

Does someone know how to solve that problem? Is it using Bragg's law? I know that in Bragg's law, the incident angle and reflection angle are the same but in the picture it is not. Problem: When ...
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Doubts with the Bragg's law of reflection

The Bragg's condition of constructive interference between two rays reflected from two parallel crystal planes separated by a distance $d$ is $$2d\sin\theta=n\lambda$$ where $\lambda$ is the common ...
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X-ray diffraction intensity and Laue equations

My textbook, Solid-State Physics, Fluidics, and Analytical Techniques in Micro- and Nanotechnology, by Madou, says the following in a section on X-Ray Intensity and Structure Factor $F(hkl)$: In ...
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Path difference between scattered x-rays

My textbook, Solid-State Physics, Fluidics, and Analytical Techniques in Micro- and Nanotechnology, by Madou, says the following in a section on X-Ray Intensity and Structure Factor $F(hkl)$: We now ...
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Derivation of Laue equations

The Wikipedia article for the Laue equations presents them as follows: Let $\mathbf{a}\, ,\mathbf{b}\, ,\mathbf{c}$ be the primitive vectors of the crystal lattice $L$, whose atoms are located at the ...
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Equivalent representations of path difference? (Laue equations and Bragg's law)

My textbook, Solid-State Physics, Fluidics, and Analytical Techniques in Micro- and Nanotechnology, by Madou, presents the following image and explanation in a section on x-ray diffraction and Laue ...
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Why we do not consider all the planes possible in a crystal for the derivation of Bragg's law?

In the derivation of Bragg's law, I've seen that a particular set of planes is considered which are parallel to each other. But in a real crystal, many planes of different angles are possible. So, ...
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Is the Compton effect observed during regular x-ray diffraction?

Here we have the standard set up to observe the compton effect. From what I understand, due to the particle like nature of light, when the x ray photons collide with the electrons in the scatterer ...
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Scattering on crystals beyond Ewald and Bragg

So I whenever we consider the diffraction and scatting using crystals, powders, basically anything crystalline in the lab using X-rays we get a bunch of theories and models. The most simple one would ...
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How is Bragg's Law related to the Phenomenon of Diffraction?

As far as I understand, bragg reflections is a geometric result which says that parallel x ray beams that are incident on atomic planes will constructively interfere at specific angles. Where does ...
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Origin of XRD Peak Asymmetry

I have been doing an introductory XRD experiment in which we measure the crystal spacing of a simple lattice (LiF) and as usual obtained data for intensity against two theta. Ideally the peaks should ...
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355 views

Why is intensity decreasing for higher orders of Bragg (x-ray)diffraction?

Bragg diffraction for x-rays by a crystal structure is governed by $$ n\lambda=2dsin\theta ,$$ where $n$ is an integer and the diffraction order, $\lambda$ is the x-ray wavelength, $d$ the lattice ...
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Bragg diffraction form an “inclined” crystal plane: which angle to consider?

Consider Bragg diffraction form an "inclined" crystal plane (i.e. not perpendicular to the normal of the crystal). I was sure that the angle of diffraction $\theta$ in bragg's law must ...
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Actual explanation of bragg's law and diffraction

When We consider X-ray diffraction by a crystal, We account for the path difference between the rays reflected by the successive lattice planes. However, Light is scattered by the atoms on the lattice ...
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Why $n=1$ in Bragg' s condition?

While studying XRD pattern , most of the time we use n= 1 in the Bragg equation. Why we prefer n=1? Why don't we use n = 2 or 3 ?
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Bragg Reflection

While reading about the experiment of x-ray spectrum and Bragg reflection, I saw somewhere that it is more accurate to measure the crystal lattice constant when considering the largest measurable ...
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Confusion About Reciprocal Lattice and Allowed Miller Indices

We discussed in class that for a given crystal, say with a triangular lattice of spacing $a=2$ angstroms, it follows from the Ewald construction that there should exist a maximum wavelength of ...
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How do I determine an unknown element if I know the diffraction lines?

I'm not quite sure if I fully understand x-ray diffraction yet. In a standard XRD experiment, if I'm given the $\theta$ values for the $K_{\alpha}$ and $K_{\beta}$ peaks, I can plug them into Bragg's ...
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How do we find the angle of incidence $\theta$ in a Bragg diffraction experiment?

Suppose I have a crystal of which I like to determine the distance $d$ between the lattice planes. We can use a Bragg diffraction experiment to do so by making a plane wave of X-ray radiation with ...
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Why use simple cubic reciprocal lattice vector to determine Miller indices?

Bragg diffraction: $$ d_{hkl}= \frac{\lambda}{2sin(\theta)}.$$ This equation would allow us to determine the lattice spacing ($d_{hkl}$) of parallel crystal planes given that we observe an intensity ...
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Confusion about interference of light in Bragg's experiment

My current understanding of Bragg's experiment is this: A collimated X ray beam was shone to the surface of a metal. If we model a metal as an aggregate of parallel planes, one X ray reflects off one ...
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How do I determine the $n$ integer in the Bragg's law?

I'm studying X-rays crystallography. The basic assumption is that if I let some X-rays scatter on a crystal the atoms act as sources of new waves. Considering two waves that hit two "neighbouring" ...
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Why, in Bragg's law, is the word “diffraction” used?

When Bragg's law is explained, the word "diffraction" is used. But, as far as I see the picture above which is often added to the explanation, it seems what happens is not diffraction but just ...
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Why can Bragg Scattering be able to postulate how much farther a ray of light will travel than another?

A very common image for the concept of Bragg Scattering is the following: If my interpretation is indeed correct, it shows an incident plane wave, and with it, two rays of light. One happens to ...
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Finding a reference or a proof for scattering matrix of a dihedral corner reflector and Bragg surface?

I'm reading the book Polarimetric Radar Imaging: From Basics to Applications, on chapter 6 it is said that: The s-matrix for a dihedral corner reflector has the form: $$S=\begin{bmatrix}e^{2j\...
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Why aren't there Bragg peaks from sublattices of the unit cell?

I've been struggling with what is probably a basic question about Bragg peaks, diffraction, and I guess geometric structure factors. Basically, as I understand it, Bragg peaks depend on the symmetry ...
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Can time crystals scatter incoming waves toward the past?

Can time crystals scatter incoming waves toward the past? I think it is a fair question to ask, albeit the answer is overwhelmingly likely NO. But since the concept is fairly new, I'm wondering if ...
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does Wavelength of light change after striking bragg's plane?

When a photon particle falls on electron, it will try to change the momentum of electron. If the conduction band is partially unoccupied, electron will move in the direction of change in momentum ...
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Why can we only observe Bragg Peaks when h, k and l are integers?

When studying Bragg's law, if we assume a cubic lattice, we can write the equation as $$ \frac{2a \sin{\theta}}{\sqrt{h^2+k^2+l^2}} = n\lambda $$ Given a value for $\lambda$ , my professor said that ...
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Diffraction angle - Bragg's Law

In the Bragg's diffraction the diffraction angle theta is equal to the incident angle because for simplicity it is convenient to derive the Bragg's law considering a straight line (representing ...
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Bragg's diffraction - Huygens' principle

When a wave with a lengthwave of the same dimension of a slit passes through a slit, each point of the slit behaves as a source of secondary waves. These secondary waves interfere each other. If ...
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Calculating the energy required to observe Bragg reflection

The distance between crystals plane is approximately $10^{-10}m$ what approximate photon energy is required to observe Bragg reflection from the planes. Can someone explain how the answer was ...
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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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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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Bragg Scattering of Thermal Neutrons [closed]

I'm currently reviewing Bragg scattering. The particular problem below has me slightly confused on whether I'm thinking about it correctly. Questions Is the problem below referring to the kinetic ...
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Difference between thin film interference and Bragg diffraction of electron

Thin film interference is given by: $2dsin\theta=n\frac{\lambda}{n_i}$, where $d$ is the thickness of film, $\theta$ is the angle between incident light and tangent to the surface, $n$ is an integer, $...
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Getting the ($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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Clarification about Bragg's law explanation

The Wikipedia has this illustration of Bragg's law and then says The two separate waves will arrive at a point with the same phase, and hence undergo constructive interference, if and only if this ...
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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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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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Why does the Debye-Scherrer procedure work (powder diffractometer)

In the Debye-Scherrer procedure a sample of crystalline powder is hit by a beam of monochromatic photons. The diffracted photons are measured with a detector. We have constructive interference of the ...
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Diffraction/Bragg's law : how does $2\theta$ come about?

I'm trying to get my head around a problem (I should have checked whether I had the answer in class, the exams are coming up now and I don't know if I'll get a lecturer response over the holidays) I ...
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Problem similar to Davison & Germer eksperiment but with more angles and the mirror reflection

The problem statement: Narrow beam of electrons hits an aluminium plate under an angle $\alpha=30^\circ$ according to the flat surface. We know the distance between two crystal planes in ...