Questions tagged [dipole-moment]

Dipole moment is the electrostatic moment generated by two opposite charges taken together, far away from the charge's locations

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What is the significance of the Dipole moment in electrostatics? No one simply multiplies the distance between charges and the magnitude of charges

What is the significance of the Dipole moment in electrostatics? No one simply multiplies the distance between charges and the magnitude of the charge without a reason
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Is there an analogous potential for magnetic moments in comparison to that of electric dipoles: $\frac{k \vec{p}\cdot \hat r}{r^2}$?

If I am not mistaken the electric potential of an electric dipole is given by: $$ V(r) = \frac{k | \vec{p}|\cos \theta}{r^2} = \frac{k \vec{p}\cdot \hat r}{r^2} $$ Where $\vec{p}$ is the electric ...
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Force between two dipoles [closed]

I am extremelly confused with this question: Basically suppose we have two electric dipoles, parallel to each other, as follows in the figure: I am supposed to show that the force is attractive and ...
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Bounded charges density different from zero

From wikipedia, the electric displacement field is $\vec D=\epsilon_0 \vec E+ \vec P$ and it satisfies $\nabla \cdot D=\rho-\rho_b$ where $\rho_b$ is "the density of all those charges that are ...
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Does the 'internal potential energy' (created by charge separation) of a dipole have any physical meaning?

If you have a dipole with charges $Q_+$ and $Q_-$ separated by a distance $d$ you could calculate the work done of separating these two charges the distance $d$ $$ \Delta U = q \Delta V = - \vec{F} \...
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Why is the Anomalous magnetic dipole moment defined as half the extra contribution to the $g$-factor?

Was there a reason Julian Schwinger or Richard Feynman officially defined the anomalous magnetic moment as half of the extra $g$-factor? $$ a = \frac{g-2}{2} $$ (equation is from the Wikipedia article ...
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About dipole moment

The picture is taken from wikipedia page https://en.wikipedia.org/wiki/Electric_dipole_moment I don't understand the formula when it comes to continuous charge distribution. But I understand this one: ...
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Do quarks have a non-zero electric dipole moment?

It is written here, in this PSE link that an electron has a measured perfect spherical charge density therefore a zero electric dipole moment (i.e. perfect monopole charge). My question is, are quarks ...
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What would be the implications in the Standard Model if we experimentally verified that the electron charge has an intrinsic electric dipole moment?

It is known also by recent experiments that the electric charge distribution in space of an electron has been measured with great accuracy to be perfect homogeneous thus essentially geometrically a ...
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Intensity of electromagnetic radiation emitted by an oscillating dipole

Is the intensity of electromagnetic radiation emitted by an oscillating dipole proportional to the modulus of the second derivative of dipole moment squared, that is: $$I\propto |\ddot P(\omega)|^2$$ ...
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Problems with selection rules and polarisation

On this website http://bingweb.binghamton.edu/~suzuki/QuantumMechanicsFiles/2-4_Polarization_of_photon_emitted_from_an_excited_atom.pdf#page72 they want to explain the selection rules and the ...
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By how much protons dipole moment inside a nucleus attenuate the culomb force between them?

By how much protons dipole moment inside a nucleus attenuate the culomb force between them? As up quarks repel more than down quarks the protons should be oriented with the positive side looking away ...
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Gauss's Law for Electric Dipole [closed]

Hello, in this question i tried applying Gauss's law for electric fields since on its Left-hand Side I will have the electric flux. My question is why is the enclosed charge not equal to zero at first ...
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NMR/EPR with an RF electric field

Is it possible to perform NMR/EPR spin alignment with an oscillating electric field instead of a magnetic field (so with a sample inside the RF electric field of capacitive plates rather than a RF ...
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Why does a neutral atom not have a dipole moment?

I wonder why a single atom has no outward dipole moment, the electron in the hydrogen atom is everywhere at the same time, with a different probability of finding it at any point within the 1s orbital,...
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What is net dipole moment of a spherically symmetric charge distribution?

There is some unknown spherically symmetric charge distribution $\rho(r)$ with total charge zero. For this charge distribution how will be monopole and dipole moment? Will they be zero or non zero? ...
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Is there a connection between the $g$-factor of $2$ and the value $1/2$ of electron spin?

When the $g$-factor of an electron ($g_e$) is approx. $2.00$, this suggests that there is a relationship with the electron being a spin $1/2$ particle. I write electron spin magnetic dipole moment as $...
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What direction does magnetic dipole moment feel force in parallel magnetic field?

Suppose I have a magnetic dipole oriented vertically in the $\hat{z}$ direction so $$ \vec{m} = m\hat{z}$$ And the position vector to it is $\vec{r} = z\hat{z}$. It's entirely on the z-axis. We're ...
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Electric dipole for a continuous charge distribution

In Wikipedia https://en.wikipedia.org/wiki/Electric_dipole_moment it is said: More generally, for a continuous distribution of charge confined to a volume V, the corresponding expression for the ...
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Multipoles as a superposition of dipoles?

While navigating on Stack Exchange, I was suddenly wondering about a possibility that I never saw described in my textbooks on electrodynamics. Suppose you have a distribution of electric charges in ...
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Multipole Expansion Intuition

So my intuition of the multipole expansion is that we have a certain charge distribution, and the ME tells us that we can approximate that distribution as a superposition of monopoles, dipoles, etc. ...
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Electric dipole moment and charge density

I came across the following expression about the electric dipole moment: $\vec p=\int_V \rho(\vec {r}')\vec r'$ But I don't understand it. What is $\vec r'$ supposed to represent and the density? Are ...
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Charge density of an electric dipole and dipole density

I am trying to visualize in my head and understand how the concepts of electric dipole charge density and dipole density can be interpreted in space or in a coordinate system. In our lecture the ...
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Does a magnetic dipole spins in a uniform magnetic field

Till now I believed that every magnet has a magnetic moment vector associated with it and that if that magnet is put in a uniform magnetic field its magnetic moment vector tries to align itself with ...
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Fourier transform of the dipole dipole interaction

One can find on wikipedia the expression for the dipole-dipole interaction in the Fourier space: wikipedia article $$-\mu_0\frac{(\vec{m}_1\cdot\vec{q})(\vec{m}_2\cdot\vec{q})-|\vec{q}|^2(\vec{m}_1\...
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Gravitatinal Dipole moments?

So, I was reading about electric dipoles, which is a system of positive and negative charges kept at a distance $d$. But I got an ideas, as to why there seems to be a lot of example of electric ...
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If the dipole moment is not unique, how can the probability of absorption depend on the angle between the dipole moment and the electric-field?

For systems with non-zero net charge, the dipole moment depends on the choice of origin (see Does the dipole moment depend on the choice of origin?). How then, can the probability of emission/...
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What do these energy level diagrams and notation mean in this Buckminsterfullerene dipole transitions question?

I have some questions about the authors' solution to the following homework style question: $C_{60}$ fullerene molecule question" /> I have added the number of electrons per level into the image, the ...
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How can the value of charge on an atom be less than that of a proton?

The dipole moment of an $\text{HCl}$ molecule is about $3.6×10^{-30} \ \mathrm{Cm}$ and the separation between the atoms of it is about $1.27×10^{-10}\ \mathrm m$. We know that dipole moment, $p=qd$. ...
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Electric dipole moment of a ring of charge [closed]

In my book dipole moment is defined for two charges. But I got a hw question to calculate dipole moment due to a ring. I tried two different methods to solve this problem but I don't think that any ...
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Force on a dipole due to another dipole

The force on a dipole (with moment $\vec{p}_1$) in an electric field is given as $\vec{F} = (\vec{p}_1\cdot\vec{\nabla})\vec{E}$ Now lets say we have another dipole with moment $\vec{p}_2$ at the ...
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Similarity between Potential Energy Function of Polarized Sphere and Cylinder

According to this paper, the potential of any point on the surface at a distance '$h$' from the center of some simple conducting geometric shape is given by For a Sphere: $$V(x)=Mh^2\frac{xcos(\alpha)+...
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Ensemble average of polarization with applied field

This question is in regard to a dipole moment fluctuation formula seen in: MOLECULAR PHYSICS, 1983, VOL. 50, NO. 4, 841-858, on page 843. For a system of polar liquid (water) at equilibrium, the ...
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How to vector integrate magnetic moment of magnetic dipoles?

I've been reading this paper - Interaction between two magnetic dipoles in a uniform magnetic field (https://doi.org/10.1063/1.4941750) and in it they derive the vector for magnetic moment of the ...
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Centre of charge of the distribution

If one has a charge distribution whose monopole moment differs from zero, how can I show that one can always find an origin such that the dipole moment will be zero?
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Potential energy of magnetic dipole in non-uniform magnetic field

I want to understand why the potential energy of an ideal magnetic dipole with dipole moment $\boldsymbol{m}$ in a non-uniform magnetic field $\boldsymbol{B}$ (neglecting the term to keep the ...
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Are neutrons polarized by the electric field of protons inside a heavy nucleus making the nucleus more 'positive'?

Are neutrons polarized by the electric field of protons inside a heavy nucleus of an atom making the nucleus more positive for the electrons? I think a spherical capacitor with unchanging amount of ...
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Factor of 2 in the Rabi frequency

This is a question about a strange literature discrepancy which I can't seem to resolve for myself. In the wikipedia article on the Maxwell-Bloch equations, the Rabi frequency is defined as $$\Omega = ...
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Polarization density

Is the polarization density term in the electromagnetic wave equation the density of static electric dipole moments or transition dipole moments?
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Transition Dipole Moment Function

A simple question: I have came across the word "transition dipole moment function" many times. I have seen it in Einstein coefficient relation or also called transition rates. In this ...
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Dielectric constant of crystals: Feynman's mistake?

Feynman mentioned in his lecture that we can, in some way, obtain dielectric constant of crystals by summing up the electric field due to dipoles. For example, equation (11.33) from above link shows ...
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Behavior of a Pointlike Dipole

I have a practice problem in my textbook that I'm not sure how to approach. It asks to find the force of an electric field created by an infinitely long line of charge of density $+\lambda_0$ (which I ...
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Is the dipole moment of a polarized particle supposed to be a constant?

Problem $4.4$ A point charge $q$ is situated a large distance $r$ from a neutral atom of polarizability $\alpha$. Find the force of attraction between them. Source: Griffiths, Electrodynamics ...
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GUI for DFT calculations

I am a beginner in DFT. Can someone suggest a good DFT software with a GUI for simulating dipole moment directions and optical absorption spectra in an organic crystal? I have tried Burai. But it ...
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If dipole moment is a vector $q×d$, then is charge a vector?

If I am right you can only do vector product for vectors. Here you have dipole moment $= q×d$. Then are we assuming charge is a vector? But how then does charge obey the triangle law of vector ...
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What is the physical significance of defining the dipole moment as a vector?

I don't know why do we need to assign a direction to some quantity which is a product of the charge and the distance bewteen charges. What is the physical reason of defining the dipole moment as a ...
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Definition of electric polarisation and the potential due to a polarised body

I've two questions, the second one depends on the first. $\mathbf{1}$ How exactly is polarisation defined? Griffiths says $\mathbf{P} \equiv$ dipole moment per unit volume How exactly do we go about ...
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Dipole moment of non-uniformly charged cylinder — direction

If we consider a cylinder along the $z$-axis, with charge density $\rho(z)$ [varying linearly according to$\rho = az + b$, from the positive value $\rho_1=-ha+b$] at $-h$ to the also positive $\rho_2=...
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Why are electronic transitions in atoms modelled as oscillating electric dipole radiation?

Sources such as Eugene Hecht and Griffiths claim that oscillating electric dipole radiation is a great approximation for radiation generated from atoms and molecules during electronic transitions. I ...
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Can neutrons be manipulated with magnetic fields? Can neutron particle accelerators be built?

Neutrons have no electric charge and do not respond to electric fields as in a conventional particle accelerator. However, they are magnetic and do have a small magnetic dipole moment. So it should ...
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