Questions tagged [electrons]

Negatively charged particle with spin 1/2. A component of mundane terrestrial matter, and part of all neutral atoms and molecules. It has a mass about 1/1800 that of a proton. Its antiparticle is the positron.

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Is it reasonable to interpret the Lamb shift as vacuum induced Stark shifts?

This is a pretty hand-wavy question about interpretation of the Lamb shift. I understand that one can calculate the Lamb shift diagrammatically to get an accurate result, but there exist "...
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Does electron have some intrinsic ~$10^{21}$ Hz oscillations (de Broglie's clock/Zitterbewegung)?

Louis De Broglie has postulated in 1924 that with electron's mass there comes some $\approx 10^{21}$Hz inner oscillation: $E=mc^2=h f=\hbar \omega$. We would get such oscillation e.g. if using $E=mc^...
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Are Electrons in a Circuit Subject to Newton's Third Law?

Consider a simple electrical circuit made up of a battery, an incandescent bulb, and wire. The battery and bulb are equal in mass and are on opposite sides of a circle made up by the wire. Lastly, the ...
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Micro-channel Plate Detectors - do they or don't they degrade?

Micro-channel plate (MCP) detectors are microscopic holes in a plate. They get put in an electric field and there act like many tiny dynodes, amplifying any electrons that enter. This makes them ...
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What is the refractive index of an electron?

Consider a free electron or electron bunch, would it have a corresponding refractive index? At low or high energies, the effects are obviously much different. I am curious to know (I haven't found) ...
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An equation in Laughlin Argument paper (1981)

In his paper Quantized Hall conductivity in two dimensions, Laughlin considers a ribbon of two-dimensional metal bent into a loop of circumference $L$, and pierced everywhere by a magnetic field $H_o$ ...
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How is interference of electrons (double slit experiment) explained in Heisenberg's Matrix Mechanics?

How is interference of electrons (double slit experiment) explained in Heisenberg's Matrix Mechanics?
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Electron hopping among molecules - Marcus equation

I'm running out of professors to talk to, and I need to clarify a couple of things for the sake of making a realistic model of electron travel through a mesh. This is about calculations of electron ...
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257 views

Is “microbunching” in a free electron laser limited by the Pauli exclusion principle?

As I understand it, a free electron laser can basically be pictured as a synchrotron light source with an undulator which by the particular setup causes the electrons to self-attune so that they ...
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Reconciling electron configuration and valence electron distribution over separate energy levels in energy band theory

This seemed like more of a chemistry question to me, but I was told by the people at chemistry.stackexchange that it might be more appropriate to post here, since "it was the physics guys that did all ...
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Detecting electron spin

Is this right?When an electron passes tnrough a detector it starts precessing but no matter of the first electrom spin orientation the highest spin magnitude is detected.In that case I am confused... ...
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Doubt about the working principle of a silicon solar cell

I'm studying crystalline solar cell and their working principle, but I still don't completely understand the process. First of all, I understand that we dope a pure crystalline silicon with boron and ...
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2answers
255 views

Electronic component of the Hamiltonian operator and uncertainty principle

This question has to do with the concept of uncertainty principle. The Hamiltonian operator has the electronic component that takes the inverse of the distance between any two electrons. My question ...
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Circular vs Sinusoidal Cyclotron Radiation

Why is the wavelength of circular cyclotron radiation different than that emitted by a non-relativistic electron passing through an undulator? From what I understand, the wavelength of circular ...
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317 views

Accelerated ion beam current

If an electron gun creates a $10\space mA$ electron beam and each electron collides with a gas atom and creates an ion through impact ionization, can the ions then be accelerated with a separate ...
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Solid state physics: When do I use classical laws?

Let's say I am given the dispersion relation for nearly-free electrons: $$ E(k) = \frac{\hbar^2}{2m}(k^2+c\,k^4)$$ Where $c$ is a small constant of appropiate dimension. How do I calculate the ...
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Rate of interaction of free electron with photons from sunlight

How many photons does a free electron (in sunlight say) interact with per second? I did a rough calculation assuming the electron interacts with any photon that enters through an area the size of ...
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413 views

Opacity/transparency of conductive meshes to charged particles (electrons/ions)

When using a conductive (metal) mesh, effectively a metallic woven fabric, in vacuum applications as a "grid" for charged particle optics, how does one calculate (or at least estimate) the opacity or ...
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Attraction and repulsion of electron spin ups and electron spin downs

Alright, we know that copper is a diamagnetic material, which has paired electrons. These paired electrons have different spin. I'm specifically interested in what is going on with the electrons in a ...
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1answer
456 views

Electrons skip randomly around their orbits

I read where the electron (as well as a few other particles) skips around in its orbit randomly rather than move around the orbit smoothly. This effect has been repeatedly observed in the laboratory ...
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1answer
188 views

Do metals have their distinctive look because of the electron sea which surrounds the metal atoms?

are metals shiny because of the electron sea which surrounds the atomic lattice of the metal sample. are metals more shiny because the electron are more evenly distributed on the surface?
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Field positive ion emission

A metal is approximately a sea of mobile electrons and a lattice of positive ions. In a vacuum, a piece of metal with enough negative charge will release electrons. Sharp points enhance this effect. ...
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Is it possible to overload a thin conductive object with electrons?

A parallel-plate capacitor is a very simple device. To make one, you can take two metal plates, separate them with a dielectric material, and voilà! You have a capacitor. Given a dielectric ...
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Do electrons and protons not want to be near each other?

In this video here posted by Kurzgesagt – In a Nutshell, at 2:01, it is said that particles like electrons and protons don't want to be near each other. Wouldn't oppositely charged particles attract ...
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Why $d,f$ electrons are more localized than $s,p$ electrons?

I’m reading Assa Auerbach’s Interacting electrons and quantum magnetism. In 1.3, it says In contrast, transition metals and mixed valence rare earth compounds contribute $d$ and $f$ electrons to the ...
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If an electron-hole pair is formed, where does the electron “go”?

I've seen the explanation before that holes are basically electron deficiencies in an atom and that the hole "moves around" by electrons from surrounding atoms shuffling to fill that spot ...
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Is there any dependence between the shape and dynamics of the electric field produced by an electron and 'shape' of its wave function?

In classical electromagnetism the electron is described by a point charge that generates an electric field with spherical symmetry when the electron is static but at the quantum level the electron is ...
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Using laser scattering beams instead detectors in Double Slit Experiment?

In the Double Slit Experiment for electrons could be possible the use of an appropriate laser pointer at one slit aiming up so when an electron passes through that distinct slit it get scattered up so ...
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Generalisation of the density states of phonons

Is it possible to generalize de density of states for phonons $\left( \left(\frac{L}{2\pi} \right )^3 \int \frac{dS_\omega}{v_g}\right)$ to a density of states which is also applicable to Bloch ...
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Can a chain reaction of photon->electron->photon->electron be possible?

Unless I'm wrong, I know that if a photon strikes an electron at the right frequency, the electron jumps to a higher energy orbit, and then comes back to its stable energy state. While coming back, it ...
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New electronic state of matter

I just heard about a new state of matter, clustered electrons. I didn't know that electrons could do that. Can anyone describe the mechanism by which this is possible? https://phys.org/news/2020-02-...
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Keldysh Field Theory: Self Energy Structure in RAK basis

Consider the Keldysh formulation of electrons interacting with each other through the Coulomb potential. Suppose that we've switched to the RAK (Retarded-Advanced-Keldysh) basis of Larkin & ...
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Spin-orbit interaction

When I derived the spin orbit interaction, I switched to the electron's reference frame, so it feels a magnetic field $B$. after calculations I get the spin orbit interaction in the electron's frame ...
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Other than the Rutherford experiment, which experiments/proofs were used to prove that the atom is mostly empty space?

I know about Rutherford's gold foil experiment and his results which led him to believe that the atom is mostly empty space. Is there any other way in which this claim could be proven?
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Why does not a free electron fall into the nucleus during elastic scattering?

When a free electron finds a hole in the medium, they can re-combine and annihilate each other. So far so good. A free electron can also scatter from positive atomic center (say it elastic scattering ...
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How to simulate the formation of chemical bonds by calculating electrodynamic forces?

I had the idea recently that if the interactions between atoms could be calculated, that a large enough computer could simulate biological processes. What would I need to know to simulate something ...
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Eigenstates in a 2D metal disk with finite-size perpendicular magnetic field (Piece-wise Gauge)

Let's have a two-dimensional metal disk with radius R, and now I apply a uniform magnetic field B perpendicular to the disk, within the concentric part of the disk with radius r $\lt$ R. How can we ...
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Single electron in conductive cavity

It is a basic result in electrostatics that a charge $q$ in an arbitrary cavity of an ideal conductor will generate a total charge $-q$ on the surface of the cavity in such a way that the electric ...
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How can the velocity of electrons in graphene be measured?

I'm trying to understand how one can measure the velocity of electrons in graphene, from an experimental point of view. Does anyone have some clue?
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How can light travelling forward send an electron forward?

Light travels along the x-axis and strikes a stationary free electron. Its E field oscillates along the y-axis. The electron moves off at an angle with respect to the x-axis less than 90 degrees. ...
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Lightning in space, would it be a perfectly straight line?

I have read this question: Can lightning happen in a vacuum? I do understand that here on Earth lightning consists of electrons moving in space and some of these electrons are tracing path, and ...
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Are / Why are the H II regions positively charged?

One of the questions in our recent astrophysics course homework was to find the general opacity $\kappa$ of H II regions. We know that the H II regions are almost entirely ionized hydrogen and I ...
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What are the prerequisites for a free electron and an atom/ion to recombine?

I'm mostly interested about recombination not in plasma (e.g., recombination of beta particles with atoms that they pass by), although the rules are probably the same. Say, there's a free electron ...
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Universal curve of inelastic mean free path - why large at low energy?

I have seen the "universal" curve of inelastic mean free path (MFP) of electrons in many places (both experimental data, and just sketches of the curve) e.g. https://en.wikipedia.org/wiki/...
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Why do salts form ions?

For example, sodium chloride is formed because a chlorine atom "takes" one electron from a sodium atom, thus forming a sodium+ and a chlorine- ion which stick together because of their different ...
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Faraday, Avogadro's Number and Atomic Mass/Size

I'm currently rereading "An Introduction to Quantum Physics" by A.P. French, and confused myself. The text reads along the lines of (paraphrased): Making the assumption that e is equal both to ...
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Hydrogen energy state transition times and probabilites

How correlated is the energy absorbed to the later energy emitted, and hence to the transition type? What is the scale of time it takes to make a downward transition in energy level? In a very cold ...
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4answers
272 views

De Broglie Wavelength interpretation

I've just started learning about the double slit experiment (just in the short appendix section in Schroeder's Thermal Physics), and I'm extremely confused by this one thing: In it, out of basically ...
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Does an electron have a frequency (and hence an energy)?

The formulation is provocative, the question is similar to the question here. There I can follow the question, but not the answers, which for me imply that an electron in a momentum eigenstate does ...
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Nearly free electron model, periodicyt and first Brillouin zone

I am taking an introductory course in condensed matter physics, and am absolutely stumped by the concept of the Brillouin zone and backfolding of the dispersion curve in the nearly free electron model....

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