Effect of relaxation of the geometric structure on the solvatochromic shift in electronic spectra of molecules

The influence of relaxation effects on the solvatochromic shifts observed in the electronic spectra of organic compounds in solvents is investigated using quantum-chemical methods. The calculations are performed in the framework of the time-dependent density functional theory. It is revealed that, in 40% of the cases under consideration, the relaxation contribution accounts for more than 20% of the total solvatochromic shift. The most pronounced effects are associated with the observed changes in the dihedral angles between molecular fragments.