Journal Article 2 first-principles study CH3NH3PbI3 perovskite building blocks 1 QTAIM and SAPT characterizations 1 Research Support, Non-U.S. Gov't 1 Ultra-strong hydrogen bonding 1 fluorine-centered noncovalent interactions 1 mehr ... hydrogen bond classification 1 molecular electrostatic surface potential 1 natural bond orbital and reduced density gradient noncovalent interaction analysis 1 quantum theory of atoms in molecules 1 weak binding energies 1 weniger ...