Hiking on the potential energy surface of a functional tyrosinase model--implications of singlet, broken-symmetry and triplet description.

The singlet, open-shell singlet and triplet potential energy surfaces (PES) for the peroxo state of a catalytic functional tyrosinase model have been investigated by density functional theory calculations. The broken-symmetry solution exhibits considerable stabilisation over the whole PES but the importance of the triplet state is unravelled as well.