Symmetry unimportance

Heretofore we have confined our discussion to spherical charges and briefly to squat cylindrical charges. For the former, gage orientation is unimportant if the spheres are centrally initiated since the disturbance will propagate outward thru the water with spherical symmetry. For... 

It in addition to the C axis, there is a horizontal plane perpendicular to that axis) the molecule is said to have symmetry. An example of this relatively unimportant group is t/vms-dichloroethene (Fig. 3.13a). If there are r mirror planes containing the rotation axis, Cn, the planes are designated vertical planes, and the molecule has Cm symmetry. Many simple inorganic... 

Fig. 8. Schematic drawing of the A,A and A.A forms of (phen)2Cr(OH),Cr(phen), lt (a) A,A Isomer—the hydrogen atoms on different ligand molecules, HH, near the plane of symmetry, are seen to be very close (b) A,A isomer—nonbonded hydrogen interactions are unimportant. Reprinted with permission from Josephsen, J., and Schaffer, C. E., Acta Chcm. Scand. 24, 2929(1970).

As in the case of the E —> A2 emission of Cr +, a weak dependence on Dq is expected. The spectroscopy of d ions is complicated by distortions from regular tetrahedral symmetry that influence electronic energies and alter the prediction of Eq. (7). In Mn + 28105, Shen et al. reported that distortion effects were unimportant above -100 kbar and that the E —> A2 luminescence energy was constant within experimental uncertainty in the absence of site distortion effects [158]. A similarly weak dependence of the E —> A2 luminescence energy was observed in Cr + Y3AI5O12 at high pressure after an electronic crossover of the T2 and E states was induced [157]. The weak shift observed for the E emission indicates only small changes in B with pressure in the d systems. 

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