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Talk:Multipole moment

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Article creation

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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

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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?

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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)[reply]


Multipole Names

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

Formula missing descriptions

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The section Multipole moments#Molecular electrostatic multipole moments introduces a lot of terms without any explanation. Some examples:

  • What is the multipole expansion expanding?
  • What are Racah's normalization and the Condon-Shortley phase?
  • What are , etc., and how are the expressions for them justified?
  • Ditto for , etc.

More explanation, links or citations are needed to make this article comprehensible. --RockMagnetist (talk) 14:14, 13 October 2010 (UTC)[reply]

Answers:

  • 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.
  • , equation is in article with substituted. For justification see expectation value, which I will link to.
  • Real form of the complex , see article.

--173.228.47.88 (talk) 17:09, 27 March 2012 (UTC)[reply]

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