Talk:Tanabe–Sugano diagram

Things This Article Really Needs

Graphics would be kinda handy for an article on diagrams, if anyone feels like putting up an example. Also an explanation of how to make UV/VIS spectroscopic predictions from these... Knowing what units a diagram used isn't actually particularly helpfull to anybody, unless they know what to do with the diagram in the first place! --Zatnik 09:45, 11 November 2007 (UTC)

Graphics for all 7 octahedral diagrams have been added, but they may not be quite as quantitative as one might wish. Two examples of predictions were added. The example already in place seems more "how to" than is appropriate for Wikipedia.

What about diagrams for Jahn-Teller distorted complexes? Chem507f091 (talk) 05:40, 16 December 2009 (UTC)

The energy level diagrams in the Unnecessary Diagrams are not properly labeled. The text uses a convention where the single electron orbitals are labeled using lower case e,t while the total state is labeled with capitals E,T. In the following diagrams, the single particle states are confusingly labeled with capital letters. (In fact, the entire left side of the d1 diagram shows a T state while the right side shows E, and vice-versa for the d9 diagram). —Preceding unsigned comment added by 69.91.178.211 (talk) 00:28, 11 November 2010 (UTC)

Tanabe-Sugano diagrams

In the section "Tanabe-Sugano diagrams" the labeling of the x-axis is not correct. The marked Δ/B-values should be given as 10, 20, 30, 40 and not as 1, 2, 3, 4 (see corresponding textbooks such as F. A. Cotton, Chemical Applications of Group Theory, 3rd edition, Wiley, New York 1990, 276-277 or C. E. Housecroft, A. G. Sharpe, Inorganic Chemistry, 2nd edition, Pearson, Harlow, 2005, 577). The mistake probably came about the fact that the older literature lists Dq/B rather than Δ/B (see the original Y. Tanabe, S. Sugano, J. Phys. Soc. Japan, 1954, 9, 766-779). In the section "Solving for B and Δ_O" the graphical representation is again erroneous, however surprisingly, the Δ/B-values used in the calculations (see Table) are correct! Please exchange the erroneously labelled graphics. Hegetschweiler — Preceding unsigned comment added by 134.96.23.51 (talk) 15:18, 30 August 2018 (UTC)

You're definitely right; I just made new diagrams with a corrected abscissa. Who knows how/when that happened. TungstenEinsteinium (talk) 14:25, 2 July 2021 (UTC)

Would it be possible to get in contact with you? Or at least if you could add a source the calculation method of the nice TS diagrams you added, as I would like to add some to my PhD-thesis.

2001:1716:4601:4240:F5F4:136C:6957:67F6 (talk) 18:47, 8 June 2023 (UTC)

Some diagrams present not enough terms in the octahedral ligand field. The sum of degeneracies for the octahedral terms does not match the degeneracy of the parent atomic term. For instance, d⁵: the ²I atomic term splits into ²T₂, ²A₂, ²T₁, ²T₂, ²E, and ²A₁. Sum of their spatial degeneracies (not counting spin degeneracy) is 13 (3+1+3+3+2+1) consistently with the 13-fold degeneracy of the atomic term I. Unfortunately, not all of these terms are shown into the d⁵ diagram provided here. I recognize that this problem is also observed for T-S diagrams reproduced in many textbooks. — Preceding unsigned comment added by 77.252.63.214 (talk) 08:39, 6 September 2022 (UTC)

This is by design. In none of the textbooks or reference works I have consulted are all states plotted in the d3-d7 Tanabe–Sugano diagrams. That is because of the large number of states (especially for d4-d6), which would leave the diagram cluttered and would obscure the more 'important' states. Generally, only 'interesting' states are selected to be plotted. Because of differences in various authors' definitions of 'interesting states', you can sometimes see different states plotted in different diagrams. In general, all low-energy spin-allowed transitions and most spin-forbidden low-energy transitions were selected for the plots on this page. The diagrams I made try to be transparent about this by leaving all atomic terms symbols on the left side of the figure, so that an interested party can determine which states have been selected for omission (as you seem to have done). If you'd like a feel for how the diagram would look if every state were plotted, you can see the d7 figure I added showing the high/low spin discontinuity (the d4, d5, and d6 diagrams are significantly busier still). If you're particularly missing the second 2T2 state from the 2I atomic term, I can add that. If you're requesting that all states be added to these diagrams, I disagree. Maybe we should have a discussion about creating a data page compiling the matrices for Tanabe–Sugano diagrams, where we can also put more detailed plots showing all possible states. TungstenEinsteinium (talk) 14:20, 2 November 2022 (UTC)