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.

377 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
6
votes
0answers
240 views

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 "...
5
votes
0answers
91 views

Free Electron-Bond Electron Interactions

I am reading an introductory textbook on electronics: Practical Electronics for Inventors by Paul Scherz and Simon Monk. In a section discussing the motion of electrons in circuits, the textbook ...
5
votes
1answer
167 views

Special conditions at layer F2 ionosphere

I saw this graph about the electrons density in different altitudes and difference between night and day, the difference between the 2 electron densities (day and night) decreases till 300 Km (F2 ...
4
votes
0answers
79 views

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 ...
4
votes
0answers
130 views

Why do electrons abide by Hund's rule?

Is the reason why Hund's rule exists, that when electrons are in different orbitals (such as 2px, 2py, or 2pz), they are most stable (lowest energy)? If the purpose is stability/lowest energy, ...
4
votes
0answers
185 views

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) ...
4
votes
0answers
133 views

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?
4
votes
0answers
313 views

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 ...
4
votes
1answer
270 views

Does electron have some intrinsic ~$10^{21}$ Hz oscillations (de Broglie's clock/Zitterbewegung)?

De Broglie has postulated in 1927 that with electron's mass there comes some inner oscillation: $E=mc^2=h f=\hbar \omega$. We would get such oscillation e.g. if using $E=mc^2$ energy in stationary ...
3
votes
1answer
59 views

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 ...
3
votes
0answers
47 views

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 ...
3
votes
0answers
309 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 ...
3
votes
1answer
74 views

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 ...
3
votes
1answer
248 views

Why is lightning going from the Earth to the clouds while the electrons are going from the clouds to the Earth?

The lightning is often a discharge in advance. The (negative) charge slide occasionally a little further on in the conductive channel, wherein said channel is highlighted each time something. The ...
3
votes
1answer
104 views

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 ...
3
votes
1answer
370 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 ...
3
votes
0answers
569 views

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 ...
3
votes
1answer
432 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 ...
3
votes
1answer
215 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 ...
3
votes
1answer
165 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?
2
votes
1answer
20 views

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 ...
2
votes
0answers
45 views

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?
2
votes
0answers
74 views

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. ...
2
votes
0answers
57 views

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 ...
2
votes
0answers
49 views

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 ...
2
votes
0answers
34 views

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 ...
2
votes
0answers
28 views

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 ...
2
votes
0answers
41 views

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 ...
2
votes
0answers
50 views

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 ...
2
votes
0answers
251 views

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 ...
2
votes
0answers
162 views

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....
2
votes
1answer
90 views

Torque on Quarter-Wave Plate

When circularly polarized light is passed through a quarter-wave plate, the plate experiences a torque. I understand this is true because angular momentum must be conserved, but I don't understand ...
2
votes
2answers
84 views

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 ...
2
votes
2answers
70 views

Poor description of electron detection in Wikipedia?

In Wikipedia's description of the Observer Effect wrt particle physics, we have this:- For an electron to become detectable, a photon must first interact with it, and this interaction will ...
2
votes
0answers
139 views

Random phase approximation for interacting electron gas

I am studying some quantum field theory from "Altland, Simons - Condensed matter field theory": in particular the RPA approximation for the free energy of an interacting electron gas at finite ...
2
votes
0answers
89 views

Massless Electrons and Effect on Graphene Mass

I've read that electrons in graphene can travel masslessly, due to the effect of the graphene crystal around them. I'd also read that the application of an electric field can change this behavior and ...
2
votes
0answers
54 views

Probability of an electron being knocked free

Why does an electron in the K-shell have a higher probability of being knocked free during X-ray than electrons in other shells?
2
votes
0answers
308 views

Volkov States in Second Quantization

tl;dr: Is it possible to recover the semi-classical Volkov states from the full second quantized electron-photon Hamiltonian in the limit of large photon numbers? What could be an possible technical ...
2
votes
0answers
146 views

Oscillating electron in the orbitals

Let us take in our case a hydrogen atom with one proton and an electron in 1s orbital. Now let us hit that electron with exactly only one ray of photon (Imaginary, don't know whether it is possible ...
2
votes
0answers
417 views

What happens when an electron collides with an atomic nucleus?

Say an electron is shot towards an atom at such a speed that a violent collision (or just a regular collision) is unavoidable, what happens to electron and the nucleus? (Also, I'm a mere highschooler....
2
votes
1answer
80 views

Do 2 conductors (1 grounded via resistor) reach equipotential, before surplus electrons drain to earth?

Case I: a negative conductor makes contact with a neutral conductor. Negative donates some electrons to neutral, until there is 0 potential difference. Then they both are slightly negative. This ...
2
votes
0answers
85 views

Did electrons, right after the big bang, all had the same handedness (like all neutrinos are lefthanded)?

It is known that all neutrinos are lefthanded (for simplicity I don't discriminate between the technicalities of handedness and helicity), though in the answers of this question one can read that the ...
2
votes
0answers
98 views

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 $H_o$ ...
2
votes
0answers
222 views

Electron - phonon interaction and perturbation theory

It might be not so clear what the question actually is, so I'll start with that: why do we often use perturbation theory for non-degenerate spectrum in solid state physics, while the spectrum of $H_0$ ...
2
votes
0answers
189 views

How to create quantum entangled electrons

I understand that one way of creating quantum entangled electrons is by splitting a Cooper pair. Is then their spin property used in the measurement, as this must always sum to $0$? If that is the ...
2
votes
0answers
114 views

On the Full scope of Hohenberg-Kohn Theorem

The Hohenberg-Kohn Theorem (HK Theorem) tells us that, knowing the electronic density in the ground state of a system of electrons, we can reconstruct the external potential up to an additive constant ...
2
votes
0answers
241 views

On two contradictory statements about the bare electron charge from two different books

Page 83 of Bruce Schumm’s book Deep Down Things: The Breathtaking Beauty of Particle Physics says that the bare charge $ e_{0} $ of an electron is infinite. However, Page 348 of Robert Klauber’s book ...
2
votes
0answers
470 views

electric field energy density for an electron

I am currently reading a chapter in a physics book covering the electric energy stored in a parallel plate capacitor. The author derives the formula for the energy density: $u = 1/2 \epsilon E^2 $ and ...
2
votes
0answers
206 views

What is the influence of QED vacuum in electron-double-slit experiments?

In a recent question on superpositions of different quarks it was explained, that the superpositions of different electric charged particles cannot exist, in contrast to strangeness quantum number. It ...
2
votes
0answers
106 views

Ionospheric electron density measurements

I've been working on measuring total electron column density (TEC) with multi frequency GPS data. In theory, signal delay caused by TEC differences should affect the code and carrier nearly evenly in ...