Protons in LaMO3: atomistic modelling and ab initio studies

A combination of atomistic simulation and quantum mechanical techniques have been used to investigate proton transport phenomena in LaMO3 perovskite-structured oxides. We examine the energetics of dopant substitution and of incorporation of water to yield hydroxyl groups. The energy barrier to proton transfer between neighbouring oxygen ions is evaluated by ab initio cluster calculations. The simulation results suggest that a key step for proton migration is the relaxation energy required for the two adjacent oxygen ions to acquire equivalent lattice environments preceding proton transfer.