Self-Scavenging of Electrons in Fe(CO)5 Aggregates Deposited on Argon Nanoparticles

Abstract

We report a dramatic difference in electron-induced decomposition of aggregates of iron pentacarbonyl [Fe(CO)5] when compared to its isolated form. The aggregates are deposited on free argon nanoparticles (clusters) with the mean size of several hundreds of atoms and interact with an electron beam of 0–25 eV energy. The negatively charged products are analyzed mass-spectroscopically. These products of various Fe/CO composition always desorb from the cluster surface; no mixed anion–Ar fragments are detected. While anions containing one iron atom show strong resonances at low electron energies (<1 eV), the yields of more complex anions show broad bands at electron energies above 5 eV. We postulate a two-center process that involves electronic excitation of one aggregate constituent and attachment of the electron with low residual energy to another aggregate constituent. The dimer anion formation appears to determine completely the aggregation of larger complexes. We draw implications of the present findings...