Valence band resonant photoemission of Mn-12 single molecules grafted on Au(111) surface

In the present work, we address the determination of the electronic structure of a monolayer of Mn-12 clusters, grafted on Au(1 1 1) substrate by a suitable functionalization, by means of X-ray absorption and resonant valence band photoemission (RESPES) spectroscopies taken across the Mn 2p-3d absorption edge. The absorption edge of the Mn-12 monolayer is compared with that - reported in literature - of bulk Mn-12, showing that the deposition procedure does not significantly affect the intimate nature of the Mn-12 cluster. Quantitative comparison between RESPES spectra data allow us to extract the Mn 3d density of states from the Mn-12-monolayer valence band spectrum, which is dominated by the Au 5d states. The shape of the experimentally obtained valence band DOS is in good agreement with the theoretical DOS, obtained by first-principle LDA + U calculations, confirming the importance of correlation effects in the determination of the electronic properties of the Mn-12 cluster. (c) 2006 Elsevier B.V. All rights reserved.