High-frequency dielectric response, changes

The end result is that high-frequency titrations give a variety of responses, including the usual V-shaped curves, nonlinear intersecting curves, and inverted V-shaped curves. The shape of a curve may vary with frequency, or at a given frequency a change in dielectric constant or salt content can change the response. 

Now suppose that excitation of the chromophore changes its dipole moment to Uhl,. Although the solvent molecules cannot reorient instantaneously in response, the dielectric constant includes electronic polarization of the solvent in addition to orientational polarization, and changes in electronic polarization can occur essentially instantaneously in response to changing electric fields. The high-frequency component of the dielectric constant is the square of the refractive index (n) (Sects. 3.1.4 and 3.1.5). If we subtract the part of the reaction field that is attributable to electronic polarization, the part due to orientation of the solvent Eor) can be written... 

The dielectric constant refers to polarization of the medium (i.e., both the electronic polarization and the physical reorientation about bonds or molecules) in response to external sources of electric field. Polarization of the electron cloud in a molecule happens quickly, so this is called the high frequency component of the dielectric constant and is represented with a small dielectric constant, say 2. The reorientation of side chains, other changes in conformation, and movement of molecules, which take more time, is the low frequency component of the dielectric response and is accorded a higher dielectric con-... 

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