Solvent effects on the energy of electronic transitions: experimental observations and applications to structural problems of excited molecules
Experimental observations about solvent shifts of absorption bands are reviewed, and correlations with various solvent properties are discussed. The theory is treated according to the Onsager model of dielectrics which shows how data like dipole moments and polarizabilities of excited states can be obtained from solvent-shift experiments. Shifts resulting from dispersion interaction and from specific solvent–solute interaction, in particular hydrogen bonding, are considered. Possible improvements in the theory of solvent shifts are briefly discussed.