An els study of the oxidation of polycrystalline Ta and Nb at room temperature

ELS has been used to characterize the initial steps in the oxidation of polycrystalline Ta and Nb in an oxygen atmosphere at low pressures (~1.3 × 10^?6 Pa) and room temperature. The results are interpreted in terms of transitions to unoccupied states above E_F and plasmon losses, and are discussed in the light of previous studies. The results show important changes in the valence band. The O 2s and O 2p bands increase in intensity during oxidation.