Insights into reactive scattering of Pu + H2 at low energies

The corrosion of metal interfaces, due to continuous exposure to gaseous hydrogen atmosphere, significantly limits the applications of plutonium-based nuclear materials in the related fields. In this work, we simplify the situations by considering the fundamental reactions of Pu atom with a single H 2 molecule, and investigate from a theoretical perspective collision dynamics of Pu + H 2 at low energies $(0.2\ \text{eV}\text{--}13\ \text{eV})$ based on ab initio potential energy surfaces. Trajectory calculation analysis shows that three main channels, the formation of the PuH 2 , the PuH fragment, and the fragmentation, exhibit different energy-dependent cross sections, from which we observed that the PuH 2 formation is non-threshold reaction, whereas the other two channels are featured by pronounced threshold effects, which is in consistent with experimental observations. In addition, we find that three-body effects can play a decisive role in the reactions since the simplified Morse potential energy surfaces can even yield spurious results in some situations.