Optical properties of molecules in solution via hybrid TDDFT/MM simulations

The optical properties of mols. in complex environments were studied within hybrid time-dependent d. functional theory / mol. mechanics (TDDFT/MM) simulation studies. The potential energy surface in the excited state is described within time-dependent d. functional theory (TDDFT). The solvent is described through a mol. mechanics approach and the effects due to the inhomogeneities of the elec. field of the solvent mols. are fully included. The results for different systems including both n -> p* and p -> p* transitions are discussed. The authors apply this TDDFT/MM technique to the study of the properties of the ground state and of the first excited singlet state of two different systems: acetone in water and aminocoumarins in water and acetonitrile. Approach yields quant. information on the solvent-induced shifts, both batho- and hypsochromic, of the electronic absorption spectra, and on the effect of a protic and an aprotic solvent on the spectral shift. [on SciFinder (R)]