Ordering of molecular dipole moments in a nanosized water cluster

A water cluster of 1000 molecules is simulated using the method of classical molecular dynamics. The calculation is performed for the "flexible" version of the TIP4P interaction potential for a constant cluster temperature of 180 K. It is found that clusters with a solid crystalline or amorphous core and a liquid-like shell are stable structures. The ferroelectric ordering of the molecular dipole moments in the central part of the cluster is found for both cluster types; this ordering is responsible for a large total dipole moment of these molecular groups. However, this effect is compensated by dipoles in the peripheral cluster layers, so that in general, the mean dipole moment of a cluster appears to be much smaller than that in the case of the random orientation of the cluster molecules.