Fig. 3: Schematic representation of the oscillation in the metal-to-ligand charge-transfer (MLCT) state and the periodic release of predominantly axial CO ligands in a metal-centered (MC) state.

a The oscillation of the two axial COs in the bound MLCT state occurs with a period of ~90 fs. b This leads to the periodic crossover to the dissociative MC states at the same frequency, which in turn produces periodic bursts of CO dissociation having a time lag of 90 fs. Orbital configurations of the ground state and specific MLCT and MC states are given.