Cybotactic cavity

A suitable probe for the general solvent effect must therefore be a polar compound. Around its dipole moment, the solvent molecules will arrange themselves as effectively as possible -in thermal equilibrium- and the interaction between the probe dipole and the solvent molecules that form the cybotactic region must be strongly altered by electronic excitation, which will result in an appropriate shift in charge the charge will then create a new dipole moment enclosed by the same cybotactic cavity as in the initial state of the transition. 

Local anisotropies (or cybotactic effects) are expres.sions of local disturbances in the bulk dielectric due to the presence of the solute. These local disturbances are always present suffice it to look at the shape of the radial distribution functions, gMS. which represent conditional probabilities of S around M the occurrence of a first peak corresponding to the first solvation shell, followed by a second less pronounced maximum, in correspondence to the second solvation shell, is pre.sent in all experimental and simulation sets of results for all real solvents. For neutral solutes (but also for anions) the standard choice of cavity radii used in all methods is sufficient to take these cybotactic effects into account. However, there are at least two cases for which special methods can be used profitably. 

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