Effect of microsolvation on the non-radiative decay of the eumelanin monomer.

Eumelanin is a polymeric structure made of di-hydroxyindole (DHI) as the basic motif. In order to understand the photoprotection process in eumelanin, it is imperative to understand the photoprocesses in its monomers. These photoprocesses are affected by the presence of neighboring molecules, such as water molecules, in the biological environment. Therefore, we elucidate the effect of microsolvation on the photoprocesses of DHI. As seen from previous studies on DHI, there are quite a few deactivation channels for the molecule subsequent to its excitation within the UV-visible range. In the presence of microsolvation, we notice that these deactivation channels change in their energetics. However, there is always the presence of ultrafast deactivation channels and in some cases the deactivation is expected to be faster in the presence of a single water molecule as compared to the gas phase.