Szabla, R.; Šponer, J. E.; Šponer, J.; Sobolewski, A. L.; Góra, R. W. Phys. Chem. Chem. Phys. 2014, 16 (33), 17617–17626 DOI: 10.1039/C4CP02074J
Ab initio studies elucidate the molecular mechanisms underlying photostability of a prebiotically plausible precursor of purine nucleotides, indicating importance of charge-transfer-to-solvent processes. We have considered the photochemistry of AICN–water clusters, while including up to six explicit water molecules. Our calculations reveal charge transfer to solvent followed by formation of an H3O+ cation, both of which occur on the 1πσ* hypersurface. Interestingly, a second proton transfer to an adjacent water molecule leads to a 1πσ*/S0 conical intersection. We suggest that this electron-driven proton relay might be characteristic of low-lying 1πσ* states in chromophore–water clusters.