Electron-induced dissociation of iron tetracarbonyl acrolein

Abstract We studied the electron beam-induced fragmentation pattern of iron tetracarbonyl acrolein, Fe(CO) 4 (CH 2 =CHCHO). We probed both the anionic fragment formation due to dissociative electron attachment (DEA) via low-energy (0 to 12 eV) electron beam interaction and cationic fragment formation due to dissociative ionisation (DI) (70 eV electron energy). The primary motivation for this work comes from the search for a suitable precursor for focused-beam nanofabrication of iron structures. It is important to study the elementary electron beam-induced reactions to characterise the potential focused electron beam-induced deposition (FEBID) precursor molecules. We employed two complementary experimental setups to study the above-mentioned processes: a trochoidal electron monochromator with a quadrupole mass spectrometer setup to study the DEA process and the CLUB (CLUster Beam setup) apparatus to study both DEA and DI. In addition, we performed density functional theory calculations to determine the reaction thresholds and understand the different reaction channels. Often, the DEA process, due to secondary low-energy electrons, leads to broadening of the deposited region and contamination due to incomplete dissociation, compromising the FEBID quality. Here we observed that in DI, the most prominent channel is bare Fe + formation, whereas production of Fe − due to DEA is weak.