Talk:Multipole moment

Article creation
Given the fact that multipole moments are used all throughout physics, engineering and even mathematics I am surprised this article does not already exist. I put up a late-night attempt at something halfway informative. I assume it will be edited many times! Perhaps I can work on this further... JustinWick 06:00, May 8, 2005 (UTC)

Multipole decomposition example
I believe it'd be really awesome to show some actual math for multipole decomposition. I think I can look up one in one of my old electromagnetism texts.

Yeah, that's great. I unfortunately know nothing about it, but I got here from the London Dispersion Force article - I assume it has a chemical/atomic meaning too, relating to dipoles? If someone could add that, that would be brilliant.

Error?
The Text says its the decomposition of a function. Shouldn't it be the decomposition of a field?
 * What do you mean by field? Karol 09:16, 7 December 2005 (UTC)

Multipole Names
It would be nice to include the method for constructing multipole names, such as hexadecapole. Zeroparallax 07:42, 15 March 2007 (UTC)

Formula missing descriptions
The section Multipole moments introduces a lot of terms without any explanation. Some examples: More explanation, links or citations are needed to make this article comprehensible. --RockMagnetist (talk) 14:14, 13 October 2010 (UTC)
 * What is the multipole expansion expanding?
 * What are Racah's normalization and the Condon-Shortley phase?
 * What are $$M_0^0$$, etc., and how are the expressions for them justified?
 * Ditto for $$C_1^0$$, etc.

Answers: --173.228.47.88 (talk) 17:09, 27 March 2012 (UTC)
 * A potential (for instance due to electric charges), see the sentences in the lede: "multipole moments are the coefficients of a series expansion of a potential" and "a multipole expansion provides an exact description of the potential and generally converges under two conditions:"
 * See   solid harmonic referred to in the same sentence: "regular solid harmonic function in Racah's normalization". I will give Condon-Shortley phase a wikilink.
 * $$M_0^0 = \langle \Psi|Q^0_0|\Psi\rangle $$, equation is in article with $$\ell=m=0$$ substituted. For justification see expectation value, which I will link to.
 * Real form of the complex $$Q^m_\ell$$, see article.


 * Thank you. I removed the missing descriptions tag. RockMagnetist (talk) 18:50, 27 March 2012 (UTC)