Charge Transfer Effects on Fe 2p X-ray Photoemission of RbMn[Fe(CN)6], K3Fe(CN)6, and K4Fe(CN)6

In the studies on the valence transition in RbMn[Fe(CN) 6 ], the Fe valence was determined by observing the binding energy of the primary Fe 2 p photoemission line, while the detailed analysis of the whole Fe 2 p X-ray photoemission spectrum (XPS) has not so far been performed both experimentally and theoretically. In the present study, the Fe 2 p XPS is calculated for [Fe(CN) 6 ] 3- and [Fe(CN) 6 ] 4- cluster models by a configuration-interaction full-multiplet theory. The result shows that the line shape of the Fe 2 p XPS is affected by ligand-to-metal charge transfer (LMCT) and intra-atomic multiplet coupling. It is in clear contrast to the Fe 2 p X-ray photoabsorption spectrum (XAS), where metal-to-ligand charge transfer (MLCT) plays an important role. It is clearly shown that the difference in the ground-state wavefunction between the [Fe(CN) 6 ] 3- and [Fe(CN) 6 ] 4- clusters is reflected in the CT satellite structures and the multiplet structures in the Fe 2 p XPS. From the analysis of the observed Fe 2 p XPS, together with the analysis of the Fe 2 p XAS, we conclude that the Fe 3 d energy level relative to the C 2 p energy level in RbMn[Fe(CN) 6 ] is considerably larger than that in K 3 Fe(CN) 6 .