Influence of external static and alternating electric fields on self-diffusion of water from molecular dynamics

Non-equilibrium molecular-dynamics simulations of liquid water have been performed in the canonical ensemble in the presence of both external static and oscillating electric fields of (r.m.s.) intensities 0.05V/A and 0.10V/A, with oscillating-field frequencies 50, 100 and 200 GHz. The rigid potential model TIP4P/2005 was used, and NEMD simulations were performed, including in the supercooled region, at temperatures ranging from 200 to 310 K. Significant alterations in the percentage dipole alignment and self-diffusion constant were found vis-avis zero-field conditions, as well as shifting of the probability distribution of individual molecular selfdiffusivities. For instance, the application of static fields was typically found to reduce the self-diffusion of liquid water, effectively due to some extent of `dipole-locking', or suppression of rotational motion, whilst diffusivity was found to be enhanced in oscillating fields, especially at high frequencies and outside the supercooled region. (C) 2020 Published by Elsevier B.V.

Automated summary

In non-equilibrium molecular-dynamics simulations of liquid water, it was found that static electric fields reduce self-diffusion while oscillating fields enhance it, especially at high frequencies and outside the supercooled region.