A novel density functional study on the freezing mechanism of a nanodroplet under an external electric field

Abstract

An electric field is one of the most favorable means to control the microscopic behavior of a nanodroplet/nanocluster, but the mechanisms to do so are still not very clear. In this work, we proposed dynamic density functional theory (DDFT) to mimic the freezing process of a nanodroplet under an external electric field (EEF). The molecular interaction is modeled by a Lennard–Jones potential plus a dipole–dipole interaction that is induced by the EEF. We found that the electric field could induce a series of structural transitions and that the droplet could form into a layered structure or a discrete lattice depending on the intensity of the EEF. Compared to molecular simulation, the transition EEF predicted from DDFT agrees more with reality. The time-dependent density profile indicates that the freezing process is nonlinear and irreversible, especially for the strong electric field case. These findings may provide insights into the control of nanodroplets and the preparation of nanoclusters.