Effect of a nickel dimer on the dissociation dynamics of a hydrogen molecule

By applying an Ehrenfest dynamics simulation on the basis of time-dependent density functional theory, we show that a hydrogen molecule can be dissociated near a nickel dimer when a single electron is excited from the HOMO level to the non-bonding LUMO level. The required excitation energy (i.e. the HOMO-LUMO gap energy) reduces to just 0.10 eV during the vibration of H₂ on the Ni₂ cluster. The calculated system shows a possible dissociation pathway of a hydrogen molecule on a nickel dimer that is the smallest system to mimic the initial stage of the spill-over process of hydrogen.