Density and Temperature Dependence of Proton Diffusion in Water: A First‐Principles Molecular Dynamics Study

New insights into proton propagation: The authors present a detailed report on the diffusion of a proton in different thermodynamic states of water. At high temperature and intermediate density, the proton—which spends more time as an Eigen complex than as a Zundel complex (see figure)—is destabilized, its migration is faster, and an incomplete Eigen complex acts as an acid with high chemical reactivity.