Inhomogeneous dielectric intensity mechanism

Work is being carried out in collaboration with Dr. W.T. Carnall in an effort to connect hypersensitivity to the structures of the crystal lattices where it is exhibited. The mechanism based on an inhomogeneous dielectric leads to an expression for the intensities of hypersensitive lines that is proportional to (12)... 

Some correlation can be established between and hypersensitivity. Thus, for a nearly planar molecule Ndl, we find is roughly 6, while for the crystal NdCl, it is only 0.9. Intense hypersensitive transitions occur in the molecule but not in the crystal. Jowever, the pyramidal Ndl produces an electric field at the Nd site, while the crystal does not so the intensity correlation does not establish the predominance of the inhomogeneous-dielectric mechanism. The issue is further clouded by the vibronic contributions that undoubtedly occur in the molecule. 

In these expressions, p is an arbitrary coefficient that measures the strength of the electric-field mechanism compared to qne based on an inhomogeneous dielectric. The values of CK can be worked out once the polar angles of any one of the three igands is specified. For example, ell - cos. The components for which M = 1 are mixed with those for which M = T 2 in C v symmetry, but if the relative mixtures are known (as they could be from Zeeman-effect data), a measurement of the three intensities would, in principle, determine p and also check the expressions above for consistency. 

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