Octahedral crystal field Tanabe-Sugano diagram

Figure 3.8 Tanabe-Sugano energy level diagram for a 3d6 ion in an octahedral crystal field. Note that some of the highest energy triplet and singlet crystal field states listed in table 3.3 are not shown in the diagram.

Figure 7 Crystal field splitting of the lower spectroscopic terms of and d ions for octahedral coordination (Tanabe-Sugano diagrams) A, ligand field parameter B, Racah parameter (for Cr + substitutedfor Ah+U1AI2O3, A = 17 800 cm and S = 665 cm ). Vertical arrows in the d ion diagram represent radiative transitions ...

Fig. 4.5 a Tanabe-Sugano diagram for 3d system in an octahedral crystal field, b one-dimensional configurational comdinate diagram representing 3d system of the low field. Parabolas represent the electronic states. The vibtonic states are indicated by horizontal lines. b Adapted from Ref. [81], copyright 2006, with permission fiom Elsevier... 

Fig. 12.3 a Tanabe-Sugano energy diagram of Mn ions (34 system) in an octahedral crystal field, b Configurational-coordinate diagram for Mn in fluoride hosts... 

Fig. 15.5 Tanabe-Sugano diagram for the electron configuration in an octahedral crystal field. Reprinted from Ref. [42]. Copyright 2013 with permission from Elsevier...

Absorption and emission of Cr(III) arises from the parity-forbidden electronic transitions in the 3d electronic shell. Crystal field split states of Cr(III) in octahedral symmetry are illustrated in the Tanabe-Sugano diagrams. The relative positions of the excited T2 and states depend on the crystal field strength (the subshell energy difference A = 10 Dq). In cases where DqIB <2.3 (low-field cases) Tj is the low state and the emission arises from the T2 to A2 spin-allowed transition. In the case of Dq/B > 2.3 (high field cases), the lowest state is E and the luminescence arises from the spin-forbidden transition from E to A2 characteristic for the R-line emission of ruby. The spin-allowed transitions are characterized by broad emission spectra and short lifetimes, contrary to the spin-forbidden emission from the E state (which sometimes is mixed with T, levels) with narrow band and long lifetimes. 

Figure 2 A Tanabe-Sugano diagram for a 3d impurity ion such as Cr. The octahedral crystal field increases along the x-axis and the energy levels split and shift as indicated. For zero crystal field the free ion LS states are indicated on the left. A dashed line indicates the crystal field strength relevant to ruby. The energy levels indicated appear in the absorption spectrum shown on the right. Luminescence is only from the lowest lying excited state, E. For materials that provide weaker field environments the T2 state is lower and much broader bandwidth emission is obtained. Reproduced with permission of Oxford University Press from Henderson B and Imbusch GF (1989) Optical Spectroscopy of Inorganic Solids. Oxford Clarendon Press.

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