Mode E-type

Note, the particular result of local rotation on the normal mode components in diagram 5 of Figure 3.23. Diagram 5 identifies one of the pair of the degenerate e-type modes of the O4 orbit, while local rotations on the vectors of diagram 5 lead to diagram 9 and the identification of the second mode of the degenerate pair of this symmetry. 

Fig. 8. Displacement pattern of a star of 48 (general) lattice points. The two components 6 and e of E-type modes arising from radial displacements of a star are shown with + representing outward displacement, - inward and a dot no displacement. The EI-modes are coupled to electronic motion at the centre, the E -modes are uncoupled. After Stevens 143I and Bates 14)...

Trigonal e-type modes (derived, for example, from the t2g or eg octahedral modes) can effect the following "inter-state" couplings of trigonal electronic components (Ea + Eh) e, (Ea + Ai) e, and (A2 + Eh) e. This has the consequence that vibronic components of the Ai(Aig) - Ai(T2g) transition can exhibit a nonvanishing CD which has been "borrowed" from the Ai (Aig)- -Ea(Tig) transition. Furthermore, vibronic components of the Ai(Aig) - Eh (T2g) transition may exhibit CD "borrowed" from both the A - Ea and Ai A2 trigonal components of the Aig - Tig transition. Heretofore, the appearance of multiple components in the Aig - ... 

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