  Water confinement inside a carbon nanotube (CNT) has been one of the most
exciting subjects of both experimental and theoretical interest. Most of the
previous studies, however, considered CNT structures with simple cylindrical
shapes. In this paper, we report a classical molecular dynamics study of the
equilibrium structural arrangement of water molecules confined in a multiply
connected carbon nanotube (MCCNT) containing two Y-junctions. We investigate
the structural arrangement of the water molecules in the MCCNT in terms of the
density of water molecules and the average number of hydrogen bonds per water
molecule. Our results show that the structural rearrangement of the H2O
molecules takes place several angstroms ahead of the Y-junction, rather than
only at the CNT junction itself. This phenomenon arises because it is difficult
to match the boundary condition for hydrogen bonding in the region where two
different hydrogen-bonded structures are interconnected with each other.
