Journal Article first-principles study CH3NH3PbI3 perovskite building blocks DFT calculations Monte Carlo method Na-ion Battery QTAIM and SAPT characterizations QTAIM and energy-based characterizations Research Support, Non-U.S. Gov't Ultra-strong hydrogen bonding bandgap and other electronic properties cathode materials charge and discharge states first principles calculation fluorine-centered noncovalent interactions halide perovskite halogen and hydrogen bonding hydrogen bond classification molecular electrostatic surface potential natural bond orbital and reduced density gradient noncovalent interaction analysis new material quantum theory of atoms in molecules weak binding energies