New version of the semiempirical theory for the effect of the dielectric properties of individual solvents on the shift of the emission spectra of solutions

The new approach proposed earlier for constructing a semiempirical theory t o explain how the dielectric properties of individual solvents affect the a bsolute solvation shift of the absorption spectra of solutions is extended to the more complex case of the change of the position of the emission spec tra of molecules accompanying the gas-solution phase transition. Particular attention is paid to quantitative methods of taking into account the contr ibution of intermolecular repulsive forces, as well as to the description o f solvate-shell reorganization processes that occur while a molecule of the dissolved substance remains in the excited state and that result in the ti me-dependent phenomenon of the fluorescence-spectra shift of the solutions. A preliminary test of the proposed theory is carried out, using as an exam ple a quantitative analysis of how the position of the fluorescence spectra of solutions of two amino-substituted phthalimides depends on the aggregat e state of the solvent. (C) 2001 The Optical Society of America.