# 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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### Molecular polarizability equation check [closed]

ChatGPT gave me an equation to calculate the molecular polarizability using the fluctuation of the dipole moment components, but I can't verify its validity because it gives me a made up reference. I'...
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### Linear approximation of the magnetic dipole field

Summary: using 3 angles to represent a magnetic dipole's orientation is redundant because the rotation around the $z$-axis of the dipole does not change the magnetic field, there are only 2 DOFs for ...
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### Magnetic energy associated with an intrinsic dipole

Generally for an Amperian dipole we have: Magnetic energy when it is placed in a uniform magnetic field is $\vec m \cdot \vec B$. We can define "a fake kind of energy" [Feynman] that can ...
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### Dipole moment in an electric system when the charges are not symmetrically distributed

Suppose we have two -q charges and +2q charge ate the corners of an equilateral triangle. Now to calculate the dipole moment suppose we assume that the +2q charge is 2 charges of +q magnitude. My ...
26 views

### Subsequent motion (time evolution) of angled dipoles in electric field

Suppose we have a system of two dipoles, each with dipole moment $\mathbf{p}=2aq$ each aligned at angles $\theta$ and $-\theta$ with the horizontal. I’m thinking of an angle bracket shape, essentially....
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1 vote
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### Net dipole moment of identical-particle system [closed]

Let $N$ identical electric charges be arranged arbitrarily in space, in such a way that each of them has a fixed position $\vec{r}_i$, a charge $q$ and a mass $m$. If I were to calculate the total ...
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1 vote
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### Direction of dipole after spontaneous emission

Consider a simple $J'= 1$ to $J = 0$ transition for an atom. If the magnetic field set the quantization along the z-direction, I am wondering what is the direction of the dipole moment after the atom ...
1 vote
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### Angular velocity vs Angular frequency

Are these two omega same? (angular frequency of a current oscillating loop and angular velocity of a rotating body)
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### Forward voltage of LEDs from quantum mechanics perspective

I have a very elementary understanding of LEDs and semiconductors altogether, but a more solid understanding of QM, and I was wondering if there was a way to explain (preferably mathematically) ...
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### Charge density arising due to a moving electric dipole should be time-dependent

Recently, I was reading an article that was trying to refute Fisher's claim regarding the expression for the magnetic moment developed due to a moving electric dipole. According to Fisher, the value ...
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### Absorption Cross Section for Two-Level Spin System in an AC Magnetic Field - Photon Picture

For a two-level spin with a energy difference of $E = h f$, where the two levels have zero dipole electric coupling and can only be driven by a magnetic field, how do I calculate the absorption cross ...
36 views

### Meaning of electric dipole moment

what is the meaning of electric dipole moment? Or why do we need to define electric dipole moment?
1 vote
344 views

### Intuition for magnetic dipole moment

The definition of the electric dipole moment of a system of charges makes sense intuitively - $$\boldsymbol {\bf p} = \int_{V} \boldsymbol {\bf r} \rho (\boldsymbol {\bf r})dV$$ describes the overall ...
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### Multipole expansion, same charges

I know dipole is defined with 2 opposite charges. That's why in EM dipoles exist, while in gravity they do not. However, I view multipole expansion as a way to describe how the distribution of charges ...
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### Understanding polarization and magnetization intuitively?

I am trying to develop a more intuitive understanding of the field produced by magnetization and polarization. I have the following image, and I can derive it from Maxwell's equations what the fields ...
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### Dipole moment and Branching ratio relation

I am looking for a good derivation of relation between dipole moment of transition and Branching ratio of the transition, is there a good textbook for this?
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### Larmor precession with an oscillating field?

With a non-polar molecule like CO2, presumably Larmor precession doesn't apply. However, CO2 has a mode of vibration that induces an oscillating dipole moment. Could something similar to Larmor ...
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1 vote
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### What does centre of mass of charge mean?

I am unable to understand what does this centre of mass of positive charge and centre of mass of negative charge mean??
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### What does centre of positive and negative charge separated by a small distance mean? [duplicate]

I dont understand the meaning of this statement that centre of positive and negative charge is separated by a small distance??
1 vote
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### Why do we make a dipole a ideal dipole?

My question is that why do we make a dipole a ideal dipole ($q\to\infty$ and $d\to 0$) …i mean i want the reason behind to take this and what is the problem of taking a charge with some magnitude (not ...
62 views

### Density of current in a Elementary Dipole

I can't understand this formula from my textbook, I'm trying to understand why the Density of Current is I*ΔZ(ΔZ is the lenght of the dipole) i mean a density of current would be I/Δs (with Δs the ...