CCL: Dipole moment calculation from non-zero charge distribution

[Marc Baaden <baaden\a/smplinux.de>]

 Sent to CCL by: Marc Baaden [baaden%a%smplinux.de]
 David,
 thank you for the very enlightening comments, suggestions and references.
 >>> "David F. Green dfgreen:+:ams.sunysb.edu" said:
  >> The standard definition of the dipole moment holds regardless of the
 net
  >> charge. [..]
 Hmm, I'd like to ask: what is the standard definition of a molecular dipole ?
 In several textbooks I found definitions along the line of "A dipole is a
 pair of electric charges of equal magnitude but opposite polarity [..]"
 which *implies* that the net charge is zero. This was also IMHO the
 "classical"
 and somewhat intuitive definition.
 I guess the second moment definition as integral over charge times position
 vector would be a better/more general definition. But what makes
 these definitions equivalent or allows to expand from one to the other ?
 (The first definition a priori breaking down for charged species)
 Also there must be a rationale to discard other definitions, eg one could
 dream up a definition of a molecular dipole as sum of all bond dipoles ?
 Are there seminal references on this ?
 Thanks,
 Marc Baaden
 --
  Dr. Marc Baaden  - Institut de Biologie Physico-Chimique, Paris
  mailto:baaden_-_smplinux.de      -      http://www.baaden.ibpc.fr
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