In Figure we also report the energy levels of M T at crucial geometries, i.e. the ones of the lowest singlet (S1) and triplet (T1) state. Interestingly, we may see that the S1 state of M T is stabilized by more than 0.2 eV with respect to the corresponding lowest singlet state of M. This observation suggests, that a nonnegligible driving force should favor the excited-state tautomerization of the chromophore. Importantly, in the tautomeric form the first singlet excited state is now more stable than T2, probably further decreasing the probability of ISC. The suitability of the tautomerization is also confirmed by the fact that the T1 state of M T , at its equilibrium geometry, is also more stable than the lowest triplet state of M. Conversely, at the corresponding equilibrium energies the ground state of M is stabilized by 0.52 eV compared to the tautomer, suggesting that the tautomerization should not be maintained after the relaxation. Yet, to be possible the tautomerization should proceed through a suitable relaxation channel, which does not encompass important energy barrier precluding its suitability in a ps regime. Differently from the case of M in gas phase, in the microhydrated system the tautomerization process cannot be described by a simple collective variable. Therefore, we will not present minimum energy path describing this process and we rather rely on the possibility of the complete and unbiased exploration of the accessible regions of the PES offered by non-adiabatic dynamics. SH dynamics has been performed on the basis of a model involving M in presence of a cluster of two water molecules, coherently from the hydration results obtained in our previous work by classical MD simulations. Figure ) Time evolution of the population of the different excited states issued from the SH dynamics, together with the inferred kinetic model.