A combined Monte Carlo/ <scp>DFT</scp> approach to simulate <scp>UV</scp> ?vis spectra of molecules and aggregates: Merocyanine dyes as a case study

The combination of a Monte Carlo (MC) sampling the configurational space with time dependent-density functional theory (TD-DFT) to estimate vertical excitations energies has been applied compute absorption spectra family merocyanine dyes in both their monomeric and dimeric forms. These results have compared those obtained using static DFT/TD-DFT approach as well available experimental spectra. Though suffering limitations related use DFT TD-DFT for this type systems, our data clearly show that classical MC provides suitable alternative molecular dynamics explore structural flexibility these donor-acceptor (D-?-A) chromophores enabling realistic description potential energy surface monomers aggregates (here dimers) thus Overall, quantum mechanics calculations, carried out implicit dioxane solvent on random snapshots, workable compromise solve combined challenge accuracy time-consuming problem not only merocyanines momers, but also dimers, up now less investigated. Indeed, simulated fairly agree ones, suggesting general reliability method.