Full geometry optimizations of the CaMn4O4 model cluster for the oxygen evolving complex of photosystem II

- A synthetic model of the photosynthetic oxygen-evolving complex (OEC) was theoretically investigated.
- The geometric and electronic structures of the model were determined.
- The model takes the unprotonated form (O5 = O2−).
- Two valence states exist in the one-electron oxidized state similar to the S2 states of the native OEC.