An anomalous dipole-dipole arrangement of water molecules encapsulated into C60 dimer

We have shown the possibility of the peculiar dipole-dipole arrangement of water molecules encapsulated in the C60 dimer based on first-principles total energy calculations within the framework of density functional theory. Our calculations showed that the ground state dipole-dipole arrangement of water molecules inside the C60 dimer is the tail-to-tail arrangement, which is the highest energy arrangement in classical electrodynamics. The decrease in charge density at the atomic sites associated with the [2 + 2] cycloaddition leads to the peculiar arrangement. Such a decrease in charge density decreases the energy cost associated with the Coulomb repulsive interaction between the O atom of water and walls of the C60 dimer. 53