The valence of individual europium atoms confined in carbon nanotubes is successfully measured by using core-level electron energy loss spectroscopy. Changes in the oxidation state at the atomic scale have been observed in Eu atomic chains exposed to oxygen. A transitory behavior has been identified where multiple atoms show a signal consistent with a sum of Eu2+ and Eu3+. This indicates that single atoms change their valence state multiple times during the reaction, suggesting that oxidation in confined spaces and with extra energy input (from the electron beam) might not be a simple one step electron transfer event.
ASJC Scopus subject areas
- Physics and Astronomy(all)