Protein induced singlet-triplet quasidegeneracy in the active site of [NiFe]-hydrogenase

- The active site of [NiFe]-hydrogenase is studied with electronic structure methods.
- Rotation of thiolate ligands makes either singlet or triplet state a ground state.
- At the experimental ligand orientation the two states become quasidegenerate.
- We discuss the implication of this degeneracy for nonadiabatic hydrogen catalysis.