Adsorption and dissociation of water molecules on the [formula omitted]-Pu[formula omitted]O[formula omitted](111) surface from an ab-initio molecular dynamics study

Abstract

Study of the water-plutonium oxide interaction is of fundamental importance in the corrosion of plutonium materials. In the present work, we report the results of adsorption and dissociation of water molecules on the α-Pu2O3(111) surface with ab-initio molecular dynamics (AIMD) simulations. We identify the stable adsorption configuration of water dimer on the α-Pu2O3(111) surface. Also, we find that one water molecule in the dimer can dissociate into hydrogen atom and hydroxyl group, and the reaction energy barrier is calculated to be 0.21 eV using climbing image nudged elastic band (CINEB) method. Electronic structure analysis shows a strong interaction between the dissociated hydrogen atom and the surface oxygen atom. Moreover, AIMD simulations at 300K and 600K confirm that the hydrogen-bonding interaction within the water clusters including dimer and trimer, as well as the hydrogen-transfer reaction, facilitates the dissociation of water clusters on the α-Pu2O3(111) surface. The obtained results can provide a way to understand the corrosion of plutonium enhanced by moisture.