Ab Initio Calculations of Absorption Spectra of Large Molecules in Solution: Coumarin C153

The results we have presented show that our new integrated computational procedure is able to predict the absorption spectra of C153, a large molecule in solution, with a high degree of accuracy (within a few hundred wavenumbers). Furthermore, the theoretical foundations of the proposed approach are conceptually easy, and the procedure is fully transferable to the simulation of fluorescence spectra and to the treatment of equilibrium/non-equilibrium regimes, thus making our method a powerful and flexible tool to investigate solvation dynamics for large systems of biological or technological interest, at least when coupled multiple-excited states are not involved. Our computational procedure is already interfaced with widely available computer programs, and thus is easily accessible to nonspecialists, which should increase fruitful crossovers between experiments and calculated and theoretical models.