Quantum dynamics study of photodissociation in phenol–water clusters

The photodissociation of hydrogen atoms from phenol-(H2O)n (n = 0, 1, 2) clusters was investigated using the direct dynamics variational multi-configurational Gaussian quantum dynamics method paired with the SA(4)-CAS(10,10)SCF/6-311+G** level of theory. All vibrational modes were included in the simulations. Hydrogen bonding of the phenol to water molecules changes the character of the 1πσ* excited state, which in turn pushes the ππ*-πσ* state crossing up in energy. This results in a lower probability of H atom dissociation from the ππ* state with increasing solvation. Dissociation from 1πσ*, as well as the effect of vibrational excitation in the phenol molecule, was also investigated.