Photofragments of Ni(CO)₄: A linear combination of Gaussian-type orbitals (LCGTO) Xα study

The photolytic reaction of Ni(CO)₄ upon UV irradiation has been studied theoretically using the LCGTO-Xα method. The origin of the observed luminescence is assigned to emission from the charge-transfer excited fragment Ni(CO)₃ based on an analysis of the involved orbitals and on total energy calculations. The theoretical results are able to explain the width of the experimental emission spectrum quantitatively, but overestimate somewhat the corresponding excitation energies. It is shown that the fragment Ni(CO)₃ itself may undergo a related photolytic reaction although a high density of excited states and reduced symmetry allow several reaction paths for the dissociation of one further metal-ligand bond.