Role of the Medium in Radiationless Conversion of the Energy of the Excited S 1 State in Equilibrium Systems with Intramolecular Charge Transfer

Using the Onsager model, the effect of molecular orientation interactions in solutions on the rate constant of radiationless conversion of the energy of the excited S ₁ state has been calculated for equilibrium systems with intramolecular charge transfer. The rate constant of the radiationless conversion of energy S ₁ — X _n is represented as a function of the polarity of the medium f() = ( – 1)/(2 + 1), where is the permittivity of a solvent. The results obtained are compared with the Marcus theory and are also used to explain the well-known literature data on the influence of a solvent on the lifetime of the S ₁ state of some carotenoids.