Electron-Proton Correlation for Hydrogen Tunneling Systems

The nuclear-electronic orbital (NEO) approach was used to provide insights in electron-proton correlation in hydrogen tunneling systems. As a practical method for potentially including sufficient electron-proton correlation to obtain delocalized nuclear-electronic wave functions for these systems, a state-averaged multiconfigurational approach was proposed. It was shown that the importance of dynamical electron-proton correlation is mainly due to the attractive Coulomb interaction. The results show that single configuration Hartree-Fock nuclear-electronic wave function is inadequate for the description of hydrogen tunneling systems.