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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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Unique lattice constant using X-ray diffraction

I recently learned about X-diffraction methods to analyse crystal lattices. One important law in this is the Bragg condition $$\lambda = 2d\sin(\theta).$$ I understand that $d$ is the distance between ...
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Why a crystal lattice with short axes would have a diffraction pattern in which spots would appear far apart using Bragg's law?

With the aid of Bragg's law, explain why a crystal lattice with short axes would have a diffraction pattern in which spots would appear far apart?
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How to determine the interplanar distance from the Miller Indeces $(h k l)$ of different lattices

I know that for cubic unit cells, there is a simple correspondence between the interplanar distance and the Miller Indeces: $d=\frac{1}{\sqrt{h^2 + k^2 + l^2}}$ What happens when we have more complex ...
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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 ...
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Monochromator crystal

A monochromator crystal is often used to select a specific energy value in a polychromatic beam of X-rays or neutrons. It exploits Bragg's law that (in the von Laue formulation) states that a crystal ...
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How can the waves interfere in X-ray diffraction?

This is the popular diagram surrounding the Bragg's law for X ray diffraction: But what I seem to not be able to understand is when they say that the reflected waves interact constructively to create ...
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What is the smallest value of the incident angle in Bragg's law?

The title of my question basically is what I want to know. In Bragg's law, $nλ = 2 d \sin{\theta}$, if we want to find, let's say, $d$, and know only $\lambda$ and $n$, but not $\theta$, what could be ...
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What is the catch behind the simple expression and explanation of Bragg's Law?

Consider how the topic of scattering by periodic crystal structures is covered in most books: Start by treating the crystal structure as a periodic potential and use Fermi's Golden Rule to show that ...
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Coherent and incoherent electron diffraction

I am learning about electron diffraction in a transmission electron microscope and was wondering about following topic: A single crystalline material will exhibit a diffraction pattern with discrete ...
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Why is Bragg's Law always presented as $n\lambda=2d\sin \theta$?

In the vast majority of texts and handbooks on Bragg diffraction, Bragg's formula is presented as: $$n\lambda=2d\sin \theta\tag{1}$$ where $\theta$ is the incident angle. But constructive interference ...
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Can raman be used to know the number of layers other than graphene?

I came across some paper where the number of layers of Graphene have been investigated by Raman spectroscopy. I found simulation websites https://instanano.com/characterization/calculator/raman/...
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Laser diffraction by synthetic Opal: how to determine "$d$"?

I'm doing some measurements with laser diffraction on a cut cube of synthetic opal. Here's a stock photo of it: The shimmering colours are due to diffraction of visible light on intermolecular planes ...
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Minimum distance for two parallel beam to interfere effectively

Following is an illustration of two parallel monochromatic beams interfering in Bragg's law experiment. For these two rays to interfere, what is the minimum distance OF required? I understand that the ...
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Using visible light to get (weak) diffraction information about crystals?

If a crystal has diameter roughly 0.25mm containing unit cells (say cubes) of about 1 angstrom on a side, there are about 2.5 million unit cells in the diameter of the crystal. Bragg's law (n$\lambda =...
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How does Bragg assigned $(h,k,l)$ values to planes in his paper?

I'm reading a Paper by Sir Lawrence Bragg on X-Ray Crystallography. I came across a paragraph which I don't understand after reading many times : In the structural diagrams of sodium chloride on the ...
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No solution to Bragg's law?

Bragg's Law provides a description for the diffraction peaks we observe when x-rays are incident on a crystal structure. We observe these diffraction peaks because the wavelength of the incident x-...
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Bragg and Raman beam splitters

In atom interferometry, what is the difference between Bragg and Raman beam splitter operations? When reading articles on atom interferometry I am finding statements such as `using a Raman/Bragg beam ...
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Is coherent source needed to observe Bragg diffraction?

In undergraduate solid state physics, derivations of Bragg scattering are often short and scarce in detail, often resorting to virtual "lattice planes" (which I do not find convincing) or ...
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Help with caption from Kittel: Can we get phase angle difference from dot product?

Can someone help me understand how the phase angle difference is just the dot product of k and r? Also, how do we get that the difference in phase angle is 2pir*sin(phi)/lambda?
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Resolution power of the Bragg law

A physical system that follows the Bragg law of diffraction, for example an electron scatter, shows interference patterns at some angle that follows the equation $nλ = 2d\sin(θ).$ Usually just the ...
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How can you show that there is destructive interference if Bragg‘s law is not fulfilled?

How can you show that there is destructive interference if Bragg‘s law is not fulfilled? For a given angle $\phi$, spacing $d$ and wavelength $\lambda$: suppose that the path difference between the ...
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Phase shifted Optical Fiber Bragg grating Response

As we know there is a narrow notch in the reflectance spectrum of a Phase shifted FBG. We have Bragg condition for reflected band of any uniform FBG. My question is that, does anyone know any relation ...
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Do the ideas of Bloch wavefunction and Bragg scattering of electrons which apply to crystals also apply to liquid Mercury?

Do the ideas of Bloch wavefunction and Bragg scattering of electrons which apply to crystals also apply to liquid Mercury ? Why is it that electrons in the liquid are not localised by the disordered ...
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What happens at the boundary of the Brillouin Zone?

I believe that at the boundary of Brilluoin Zone i.e, at -π/a,π/a. Taking k=π/a we have k=2π/λ so λ=2a. Making the group velocity zero. Does it point to Braggs law? What does it really signify?
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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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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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