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The majority of the text here appears to be copied directly from the source listed in the article. Is this kosher? Man It's So Loud In Here ( talk) 23:31, 6 December 2007 (UTC) reply

Well spotted, I have previously done some work on this article without checking the listed source. The article should be rewritten to avoid possible copyright issues. It's fine to use the information from the source, but not the exact same wording. -- DJIndica ( talk) 20:56, 7 December 2007 (UTC) reply

I was confused on an issue and when I didn't find my answer here I looked elsewhere and found that I was reading the same text. I think I understand now though: d is the system's dipole moment, which can be cast in the form of a quantum mechanical operator, while the matrix element ${\displaystyle \scriptstyle {\mu _{nm}}}$ is the transition (dipole) moment. I think I find it so confusing because use is inconsistent in the literature I've read. Man It's So Loud In Here ( talk) 02:02, 10 December 2007 (UTC) reply

I think the confusion stems from the classical vs quantum mechanical definitions; I have tried to clear that up, as well as rewrite to avoid any copyright issues. -- DJIndica ( talk) 23:33, 10 December 2007 (UTC) reply

Tell me if I say bullshit, but isn't it that in the definition of the transition dipole moment, Ψ represents only the electronic spatial coordinate part and not the full wavefunction of the system? (I mean, not the nuclear/vibrational function, nor the spin function)... if yes, maybe it should be said explicitly... -- Der.Gogo ( talk) 15:36, 14 September 2011 (UTC) reply

Is it OK that in 1st definition d is given as a vector quantity whereas d_mn defines an element of matrix d? No, it is not OK. d operator must be defined as a one proportional to Pauli matrices d ~ (sx,sy,sz) so that it forms a vector with operators inside (a tensor operator). Consider how confusing the current definition is, if to attempt a construction of -d.E. For this case both must be operators (matrix form). If d is defined as a vector, then E must also be defined as a vector, but then d_mn is meaningless, because it defines d as a matrix, not a vector. Tormondo ( talk) 14:48, 30 December 2011 (UTC) reply