Electric dipole moment of the nucleus of an atom

Click For Summary

Discussion Overview

The discussion centers around the electric dipole moment of the nucleus of an atom, particularly why it is considered to be zero. Participants explore the assumptions and concepts related to hyperfine interactions, monopole and quadrupole interactions, and the implications of charge distribution symmetry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the assumptions leading to the conclusion that the electric dipole moment of the nucleus is zero, suggesting that symmetry of the nucleus should be considered.
  • Another participant mentions T-symmetry and Schiff moments as relevant concepts in this context.
  • There is a discussion about the nucleus being treated as a charge distribution and the use of multipole expansion for approximating electrostatic interactions.
  • Some participants express confusion about the assumptions that result in the dipole term being zero, indicating a desire for clarification and literature references.
  • A later reply emphasizes the importance of understanding the Schiff moment, suggesting that it is a critical concept in this discussion.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the assumptions behind the electric dipole moment being zero. There is no consensus on the specific assumptions or the implications of T-symmetry and Schiff moments.

Contextual Notes

Participants reference concepts that may require further exploration, such as T-symmetry and Schiff moments, indicating potential limitations in their current understanding of these topics.

tamir
Messages
4
Reaction score
0
TL;DR
Why is the electric dipole moment of the nucleus of an atom equal zero?
Summary: Why is the electric dipole moment of the nucleus of an atom equal zero?

Summary: Why is the electric dipole moment of the nucleus of an atom equal zero?

I read about the hyperfine interactions that cause the altering of the energy levels of the nuclues of an atom. Under the discussion about monopole and quadrupole interactions, the term of the dipole moment interaction was determined to be zero because the nucleus has no electric dipole moment. My question is, what are the assumptions leading to this result? It seems like the only assumption that was taken into account was the nucleus being a positive charge distibution and it does not make sense to me considering the expression of the electric dipole moment. I would assume that some sort of symmetry of the nucleus need to be considered as well.
 
Physics news on Phys.org
Are you asking about Schiff moments or T-violation?
 
Vanadium 50 said:
Are you asking about Schiff moments or T-violation?
To my understanding it is more simple than that.
The nucleus is considered as merely a charge distribution and the electrostatic energy of the interaction between the nucleus and the electron is approximated using multipole expansion.
What I do not understand is, what are the assumptions that result with the dipole term being zero?
 
Well, one would be T-symmetry. The other would be the Schiff moment.
 
Vanadium 50 said:
Well, one would be T-symmetry. The other would be the Schiff moment.
Can you refer me to literature of those subjects?
I must admit that it seems a little bit over the top, because what I read involved more basic concepts.
As I wrote at my post, I would have assumed that some sort of symmetry of the charge distribution of the nucleus leads to its electric dipole moment being zero.
 
tamir said:
Can you refer me to literature of those subjects?

Can you tell me where you have already looked?

tamir said:
I would have assumed that some sort of symmetry of the charge distribution of the nucleus leads to its electric dipole moment being zero.

And had you Googled "Schiff moment" (which I note in passing is the third time I wrote this) you would have learned about this. I can point you in the right direction, but I can't pour knowledge into your head.

A guy prays: "Dear Lord, please make me win the lottery."
The following day he begs the Lord again: "Please make it so I win the lottery, Lord!"
The next day, he again prays: "Please, please, dear Lord, make me win the lottery - you know how much I need the money."
Suddenly there is a thunderclap and a booming voice from the heavens: "Work with me here. Buy a doggone ticket!"
 
  • Haha
  • Like
Likes   Reactions: Klystron and Cryo

Similar threads

Undergrad Instantaneous dipole moment and orbitals
  • · Replies 2 ·
Replies
2
Views
970
Graduate Transition dipole moment: cause or result of interaction?
  • · Replies 11 ·
Replies
11
Views
4K
Undergrad EM Radiation of "Permanent" Molecular Electric Dipoles
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Question regarding how to interpret dipole moment for bound charges
  • · Replies 1 ·
Replies
1
Views
2K
Graduate About diagonal element of dipole
  • · Replies 10 ·
Replies
10
Views
3K
Why is a current ring approx a magnetic dipole from very far off?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Schiff moment in classical electrostatics
  • · Replies 28 ·
Replies
28
Views
2K
Image Theory for an Electric Dipole
  • · Replies 14 ·
Replies
14
Views
3K
Graduate No Permanent Dipole Moment in Two-Level System w/External Field
  • · Replies 3 ·
Replies
3
Views
2K
How Does the Nuclear Quadrupole Moment Explain Nucleus Deformation?
  • · Replies 6 ·
Replies
6
Views
3K