Radiolytic oxidation of single crystal graphite. Nature of active species and G values

Abstract

Two processes are involved in the gasification of graphite by γ-radiation. Species, tentatively identified as ground-state-oxygen atoms in O₂ and CO₃ in CO₂, leave vacancies in basal planes which are subsequently expanded by the reaction of mobile surface oxides. The surface oxides may be generated from gaseous ions. G(vacancy formation) in oxygen and CO₂ is about 4 × 10^–8 and the G(–C) is 1.45 in CO₂ and 5.1 in O₂. The transient changes in oxidation rate at the beginning of reaction are analyzed, and all results are shown to be consistent with work on bulk graphite.