Gas-phase metal oxidation reactions studied by chemielectron spectroscopy and chemiion mass spectrometry: reactions of cerium and lanthanum with O2(X 3Σ –g), O2(a 1Δg) and O(3P)

Abstract

The gas-phase reactions M + O₂(X ³Σ^–_g), M + O₂(a ¹Δ_g) and M + O(³P) have been studied with chemielectron spectroscopy, where M represents one of the lanthanide metals, cerium or lanthanum. Assignment of the observed bands has been assisted by mass analysis of the ions produced and by approximate kinetic modelling calculations. For the M + O₂(X ³Σ^–_g) and M + O₂(a ¹Δ_g) associative ionization reactions, most of the excess energy appears as electron kinetic energy, whereas for the M + O(³P) reactions a larger fraction of the reaction energy is retained in the positive ion.