Inner-shell excitation of ethanol cluster at O K-edge

Inner-shell excitation of ethanol cluster was investigated using a partial-ion-yield method at the oxygen K-edge. The resonance feature corresponding to the excitation to the 3sa′ unoccupied orbital was not observed in the partial yield spectra of cluster ions, while it is clearly seen in the total ion yield spectrum. The absence of this feature is explained by the changes in local electronic structures owing to the hydrogen bonding in the clusters.